It's almost seven in the evening when FatPanda leaves the rain-streaked building on Datong Road. June in Shanghai is a time of sweltering humidity and frequent downpours. The roads and pavements shine, cars and trucks hiss by in a shudder of exhaust, and the heat rises in waves from the wet tarmac. FatPanda is neither a young man nor a fit one, and his shirt is soon clinging sweatily to his back.

In the eight years of its existence, the White Dragon crew has hit the best part of a hundred and fifty military and corporate targets. Initially in the U. S., more recently in Russia and Belarus. Like most of its victims, Talachyn has offered only token resistance. A week ago, a junior employee received an email that purported to come from the company's director of security, inviting him to click on a link for information about a new firewall. In fact, the link contained the ZeroT downloader, a remote-access tool designed by FatPanda, giving his crew the run of Talachyn's operational files.

But it's been a good day. He and his White Dragon crew have launched a successful spear-phishing assault against a Belarusian company named Talachyn Aerospace, and have just begun the wholly satisfying business of draining the company's data, stealing passwords and project files, and generally making merry with its most sensitive information.

Ignoring the crowds of home-going workers and the clammy heat, FatPanda walks unhurriedly through the evening haze of the Pudong district, gazing around him with admiration at the city's trophy skyscrapers. At the soaring glass column of the Shanghai Tower, the silver-blue sliver of the World Financial Centre, and the vast, pagoda-like Jin Mao Tower. That things are rather less spectacular at street level, where beggars rummage through garbage-bins, is not of concern to FatPanda.

Since these relate to classified fighter-jet designs they will be of particular interest to FatPanda's superiors in Beijing. For the White Dragon group are not, as some have thought them, merely a gratuitously destructive team of hackers and anarchists. They are an elite cyber-warfare unit of the Chinese People's Liberation Army, engaged in targeted attacks on foreign corporations, military intelligence systems and infrastructure. The anonymous-looking building on Datong Road has been fitted out with banks of powerful computer servers and high-speed fibre-optic lines, all of them cooled by precision air-conditioning systems. FatPanda, the team's leader, is Lieutenant Colonel Zhang Lei, and it was he who chose the crew's title. A moon-white dragon, according to Chinese symbolism, embodies a ferocious supernatural power. It is an omen of death. A warning.

The information they've acquired, and the identities of FatPanda and his team, have been passed up the line. As yet, no Western or Russian administration has risked confrontation with Beijing by directly accusing the People's Liberation Army of state-sponsored data-theft; the diplomatic fallout would be too damaging. But others have been less concerned with such sensitivities. The predations of White Dragon have cost their victims billions of dollars over the years, and a group of individuals, collectively more powerful than any government, has decided that it is time to act.

He is, in many ways, a clever and even brilliant man. He is certainly a lethal cyber-warrior. But success has led FatPanda to make a cardinal strategic error: he has underestimated his enemy. While he and his crew have been rummaging through the intellectual property of foreign corporations, diverting terabytes of secret data to Beijing, the world's intelligence agencies and private security firms have not been idle. Their analysts have been amassing their own data: identifying Internet protocol addresses, reverse-engineering the White Dragon crew's malware, and following their actions keystroke by keystroke.

Villanelle arrived in Shanghai a week ago.

A fortnight ago, at a meeting of the Twelve at a private seafront estate near Dartmouth, Massachusetts, Lieutenant Colonel Zhang Lei was the subject of a vote. All of the fish placed in the velvet drawstring bag were red.

FatPanda proceeds through the crowds and the diesel fumes of Pudong towards the Dongchang Road ferry terminal. He has been trained in the techniques of counter-surveillance, but it has been some years since he practised them with any real assiduity. He is on his own turf, and his enemies are continents away, little more than flickering usernames behind transparent passwords. That his actions could have deadly consequences has never seriously occurred to him.

Perhaps this is why, as he steps onto the ferry, he takes no notice of the young man in the business suit, just metres behind him, who has tailed him from his office, and who speaks briefly into his phone before vanishing into the hurrying throng on Dongchang Road. Or perhaps it's just that Lieutenant Colonel Zhang Lei's mind is elsewhere. For this prince of cyber-spies has a secret of his own, of which his colleagues know nothing. A secret which, as the ferry noses into the polluted currents of the Huangpu river, charges him with a dark thrill of anticipation.

He looks ahead of him, seeing and not seeing the illuminated panorama of the Bund, the kilometre-long waterfront on which stand the landmark edifices of old Shanghai. His gaze traverses the former banks and trading houses without interest. These monuments to colonial power are now luxury hotels, restaurants and clubs, the playground of rich tourists and the financial elite. His own destination lies beyond this gilded facade.

As he leaves the ferry at the South Bund terminal FatPanda performs a cursory sweep of his surroundings, but once again fails to register the operative reporting his progress, this time a young woman in the uniform of a hotel employee. Fifteen minutes later, he has left the Bund behind him, and is hurrying through the narrow, intersecting alleyways of the Old City. This district, teeming with shoppers and tourists, fragrant with moped exhaust and the fatty tang of street-food, is a far cry from the monumental splendour of the Bund. The pinched lanes are hung with laundry and loops of electrical cable, stalls attended by squatting women are piled high with rain-damp produce, tiny shops behind bamboo-pole awnings sell fake antiques and retro-styled girly calendars. As FatPanda turns a corner a pimp on a scooter gestures towards a dimly lit interior in which rows of young prostitutes wait and whisper.

The first floor is given over to more or less conventional sexual pleasures. As FatPanda climbs the stairs he is afforded a glimpse, through a briefly opening door, of a pink-lit room and a girl in a baby-doll nightie.

"Mr. Leung," she says brightly, consulting her laptop. "Please, go right on up." He knows that she knows that Leung is not his name, but in the house on Dangfeng Road, a certain etiquette prevails.

The second floor is altogether more specialist. FatPanda is met by an unsmiling young woman dressed in a crisp green and white skirted uniform. She wears a starched cap pinned to her upswept hair, a surgical mask, and a transparent plastic apron which rustles as she moves. She smells of some austere disinfectant. A name tag pinned to her chest identifies her as Nurse Wu.

His pace urgent now, his heart pounding, FatPanda hurries past these temptations. His destination is a three-storey corner building on Dangfeng Road. At the entrance, he keys in a four-figure code. The door opens to reveal a middle-aged woman behind a reception desk. Something in the fixity of her smile suggests extensive maxillo-facial surgery.

"I'm sorry," FatPanda whispers. He's already so excited that he's trembling.

"Remove your clothes and lie down," she orders, indicating a pink hospital gown. The gown barely reaches FatPanda's fleshy hips, and as he takes his place on the gurney with his genitals exposed, he feels profoundly, thrillingly vulnerable.

"You're late," she says icily.

Frowning, Nurse Wu leads him into a room dominated by a gurney, several monitors, and a ventilator. Beneath the ceiling light, an array of scalpels, retractors and other surgical instruments gleam dimly on aluminium trays.

Beginning with his arms, Nurse Wu begins to fasten a series of canvas and Velcro restraints, pulling the cuffs so tightly around FatPanda's chest, thighs and ankles that he is completely immobilised. The final restraint encircles his throat, and with the strap secured, she places a black rubber oxygen mask over his nose and mouth. His breathing is now audible as a shallow, urgent hissing.

"You understand that all this is for your own good?" says Nurse Wu. "Some of the procedures you require are highly intrusive, and may be painful."

FatPanda manages a faint groan from inside the mask. His panicked eyes skid around. For an instant, inches in front of his face, Nurse Wu's plastic apron falls forward and her gown parts to reveal a plump crotch in a pair of utilitarian, possibly military-issue, knickers.

"Now!" she says, and he hears the snap of latex gloves. "You need a full bladder-flush. So I'm going to have to shave and catheterise you."

FatPanda hears water running, feels the blood-temperature warmth as she lathers his pubic area and begins to scrape away with a surgical razor. Soon, his penis is rearing and twitching like a marionette. Laying down the razor, her eyes thoughtful above the three-ply surgical mask, Nurse Wu reaches for a pair of locking forceps from the tray. Holding them briefly in front of his face, she clamps the sharp teeth of the forceps onto the base of his scrotum. FatPanda looks up at her adoringly, tears of pain running down his cheeks. Once again, as if by the sheerest accident, he is permitted a glimpse of Nurse Wu's pillowy pudenda. He hears the clink of metal, feels the forceps lifted, and a moment later feels a fiery sensation tearing across his perineum.

"Now look at what you've made me do," Nurse Wu murmurs exasperatedly, holding up a scalpel with a red-tinged blade. "I'm going to have to stitch that."

FatPanda regards her with hazy surprise. A new practitioner is a departure from the scenario that he hasn't anticipated.

Tearing open a sterile pack, she takes out a monofilament suture line, and sets to work. The first entry of the needle makes FatPanda gasp, and as Nurse Wu wrenches the surgical knot tight, he shudders with barely containable pleasure. Frowning at this impertinence, Nurse Wu takes a chromium-plated probe from an ice-filled kidney dish, and inserts it forcibly into FatPanda's rectum. His eyes are closed now. He's in the zone, the place where terror and ecstasy meet in a dark, swirling tide.

And then suddenly, soundlessly, Nurse Wu is gone. FatPanda eyes drowsily revolve, scanning their limited field of vision, and another, different figure swims into view. Like Nurse Wu, she is dressed in surgical scrubs, cap, face-mask and gloves. But the eyes that are gazing at FatPanda are not amber brown like Nurse Wu's. They are the icy grey of the Russian midwinter.

Pure carbon monoxide is odourless and tasteless. To the haemoglobin in the human body it is indistinguishable from oxygen. With the first cold rush of the gas into his nostrils, FatPanda feels the threads of reality drifting away. Twenty seconds later his breathing ceases.

Villanelle can tell from his expression that he understands what she has said. Not that she doubts for a moment that a man who has spent the best part of a decade reading the confidential files of international corporations is fluent in English. From a bag at her feet she takes an aluminium cylinder, just nine inches long. Disconnecting the airflow from the oxygen tank to FatPanda's rubber mask, she attaches it to the cylinder.

"I'm afraid things have got very serious," she tells him, in English. "That's why I've been called in."

FatPanda's eyes shine with fearful anticipation. A gweipo surgeon. The clinic have excelled themselves.

When she's sure that he's dead, Villanelle reconnects the rubber mask to the oxygen. She has no doubt that someone with the specialist skills of Lieutenant Colonel Zhang Lei will receive a very thorough autopsy indeed, and that the true cause of his death will swiftly be revealed, but there's no harm in sowing a few seeds of confusion.

As an artistic touch, Villanelle slips off Nurse Wu's knickers and places them over FatPanda's head. Then, taking out a cheap mobile phone she has bought for cash that afternoon, she photographs him from a number of angles, none of them flattering. A final click emails the pictures, with a pre-written commentary, to half a dozen of China's most influential bloggers and dissidents. This is one story the Beijing establishment is not going to be able to cover up.

If there is a house rule common to the world's pleasure-houses, it is that the customer who is arriving must not meet the customer who is leaving. In the Dangfeng house a back stair leads to the exit, and it is this that Villanelle now takes, having changed from her surgical uniform. Outside, the streets are humid, and still teeming with tourists and strolling families, and no one takes any notice of a young Western woman wearing a baseball cap and carrying a small backpack. When pressed -- and in the days and weeks to come there will be hard questions asked in the lanes and alleyways of the Old Town -- one or two observers will recall that the woman's cap carried the insignia of the New York Yankees, and that her dark-blonde hair was worn in a ponytail, and from these slender impressions will be born the rumour that the suspect is an American. Frustratingly for the intelligence services and the police, no one will recall her face.

Kneeling, she examines the prostrate form of Nurse Wu. When Villanelle clamped a latex-gloved hand over her mouth, punched a hypodermic needle into her neck and injected a carefully measured dose of etorphine, the young Shanghainese woman managed a faint mew of surprise before slumping backwards into Villanelle's arms. Minutes later she still looks startled, but her breathing is steady; she will be conscious again in half an hour.

As always on these occasions, the current of Villanelle's emotions ebbs and flows. There's satisfaction at a job well done. Detailed research, imaginative planning, and a clean, silent kill. Could anyone else have taken out FatPanda with such style, such frictionless ease? In her mind she replays his last moments. The surprise as their eyes met. Then that curious acceptance as he began the drift into the depths.

Hours have passed, and Villanelle is lying in a claw-footed bathtub in a tenth floor apartment in Shanghai's exclusive French Concession, meditating upon the murder that she has just committed. The water is scented with essence of stephanotis, the walls are jade-green, silk curtains billow in the faint breeze.

Ten minutes' walk is enough for Villanelle to dispose of the phone, battery and SIM card in separate restaurant garbage bins. The scrubs, gloves, mask and cap, together with the aluminium CO cylinder, sink to the murky bed of the Huangpu river in a string shopping bag weighted with stones.

There's satisfaction, too, in the importance of her role. It's exhilarating to stand at the still centre of the turning world, and to know yourself an instrument of destiny. It makes up for the savage humiliations of her years as Oxana Vorontsova to know that she is not cursed, but blessed with a terrible strength.

Of all those humiliations, it's her rejection by the French teacher, Anna Ivanovna Leonova, that she still feels most keenly. A single woman in her late twenties, Leonova was more than a little awed by her troubled pupil's precocious linguistic gifts, and ignoring Oxana's rudeness and gracelessness, determined to open her eyes to a world beyond the grey confines of Perm. So there were weekend sessions in Anna's tiny apartment, discussing Colette and Fran?oise Sagan, and on one memorable occasion a visit to the Tchaikovsky Theatre, to see a performance of the opera Manon Lescaut.

Oxana was bemused by the attention. No one had ever expended so much time on her. What Anna Ivanovna was giving her, she realised, was something selfless, something close to love. Intellectually, Oxana understood such an emotion, but she also knew herself incapable of feeling it. Physical desire, though, was another matter, and she lay awake, night after night, tortured by a raw longing for her teacher that she could find no way of expressing beyond a sullen blankness.

She tried, just once, to take things further with Anna. It was the evening they went to Manon Lescaut. They were sitting in the balcony, in the back row of seats, and towards the end of the opera Oxana had inclined her head against the teacher's shoulder. When Anna responded by putting an arm around her, Oxana was so overwhelmed she could hardly breathe.

Not that the teenage Oxana was a novice when it came to sex. She had tried both men and women, and found no difficulty in manipulating both. But with Anna she dreamt of a realm of the senses that lay beyond the beery fumblings of bikers behind the Bar Molotov, or the rough tongue of the female security guard at the TsUM department store who had caught her stealing, marched her to the toilets, and buried her face between Oxana's thighs as the price of silence.

As Puccini's music swirled around them, Oxana reached out a hand and laid it over one of Anna's breasts. Gently, but firmly, Anna removed the hand, and equally firmly, a moment later, Oxana replaced it. This was a game she had played many times in her mind.

"What?" She parted her lips, her eyes searching for Anna's in the half dark.

"It doesn't mean… that."

"Don't you like me?" Oxana whispered.

"Stop it," Anna said quietly.

But Anna resisted this transformation. Even though, deep down she felt exactly the same way, and Oxana knew this to be true, because she had felt the flutter of the other woman's heart beneath her hand. It was intolerable, unbearable. And there in the theatre doorway, one hand thrust down the front of her jeans, Oxana gasped out her frustration until she sank to her knees on the icy pavement.

The teacher sighed. "Oxana, of course I do. But that doesn't mean…"

She was too furious to care. Why didn't Anna Ivanovna want her? That culture stuff was all very well, but she needed more from Anna than that. She needed to see desire in her eyes. To see everything that gave her power over Oxana -- her gentleness, her patience, her fucking virtue -- dissolve into sexual surrender.

"Then fuck you, and fuck your stupid opera," Oxana hissed, rage rising uncontainably inside her. Standing, she stumbled towards the exit, and ran down the staircase to the street. Outside, the city was lit by the sulphurous glow of night, and flurries of snow whirled in the car headlights on Kommunisticheskaya Prospekt. It was freezing cold, and Oxana realised that she had left her jacket inside the theatre.

Anna forgave her for her behaviour at the Tchaikovsky Theatre, but Oxana never quite forgave Anna, and her feelings for her teacher took on a morbid, angry cast.

With Anna's reaction, Oxana's world collapsed. She'd hoped for gratitude, admiration, profuse thanks. Instead the teacher had stared at her in icy, horrified silence. Only her knowledge of the conditions that Oxana would face in a women's penitentiary, Anna said, prevented her from contacting the police immediately. She would remain silent, but she never wished to see or speak to Oxana again.

Oxana was never questioned, and if she'd have preferred her victim to die of shock and blood loss, at least she had the satisfaction of knowing that he'd be pissing through a tube for the rest of his life. She'd said as much to Anna Leonova, laying the story at her teacher's feet like a cat bringing home a mutilated bird.

When Anna was sexually assaulted, matters reached a head. Taking her father's combat knife, Oxana lured Roman Nikonov into the woods, and put things right. Nikonov survived, which wasn't part of her plan, but otherwise things went perfectly.

In the end, though, Oxana did nothing. And the part of her that had yearned so desperately to make Anna her own simply froze.

The injustice of it, and the lacerating sense of loss, brought Oxana to the brink of suicide. She considered taking her father's Makarov pistol, going round to Anna's place, and shooting herself. Showering the little flat on Komsomolsky Prospekt with her blood and brains. Perhaps she'd have sex with Anna first; a 9mm automatic was a pretty persuasive seduction accessory.

She knows that she should lie low. That to go out on the prowl for sex, tonight of all nights, would be reckless. But she also recognises the hunger inside herself. A hunger whose grip will only tighten. Stepping from the bath, wreathed in steam, she stands naked in front of the plate glass, and considers the infinity of possibilities before her.

Lying in the scented water in the Shanghai apartment, Villanelle feels her earlier elation displaced by an undertow of melancholy. She turns her head towards the window, a sweep of plate glass framing the glimmering dusk and the rooftops of the French Concession, and bites pensively at her upper lip. In front of the window is a Lalique bowl of white peonies, their petals soft and enfolding.

It's after midnight when she walks into the Aquarium. The club is in the basement of a former private bank on the North Bund, and entrance is by personal introduction only. Villanelle was told about the Aquarium by the wife of a Japanese property developer whom she met at the Peninsula Spa in Huangpu. A stylish, gossipy woman, Mrs. Nakamura explained to Villanelle that she usually went there on Friday nights. "And alone, rather than in the company of my husband," she added, with a meaningful sideways glance.

Certainly the name Mikki Nakamura is one the doorman knows. He shows Villanelle through an interior door to a spiral staircase winding down to a spacious, dim-lit subterranean chamber. The place is crowded, and an animated buzz of conversation overlays the muted pulse of the music.

For a moment Villanelle stands at the foot of the stairs, looking around her. The most striking feature is a floor-to-ceiling wall of glass, perhaps ten metres long. A moving shadow darkens its luminous blue expanse, and then another, and Villanelle realises that she is looking into a shark tank. Hammerheads and reef sharks glide past, the underwater lights painting their skins with a satin sheen.

"Dead eyes," says Mikki Nakamura, materialising beside her. "I know too many men who look like that."

Mesmerised, Villanelle makes her way towards the tank. The smell of the club is that of wealth, a heady mix of frangipani blossom, incense and designer-scented bodies. In the tank a tiger shark drifts into view, and fixes Villanelle with its blank, indifferent gaze.

"We all do," says Villanelle. "And women, too."

Villanelle mirrors Mikki's smile and compliments her on her own outfit. At the same time, she's running a security check, scanning the club for anything or anyone out of place. For the nondescript figure in the shadows. The eyes that look away too quickly. The face that doesn't fit.

Mikki smiles. "I'm glad you came," she murmurs, running a finger down Villanelle's black silk qipao dress. "This is Vivienne Tam, isn't it? It's lovely."

Her attention is snagged by a willowy figure in a white halter-top and miniskirt. Mikki follows Villanelle's gaze and sighs. "Yes, I know what you're thinking. Who let the dogs out?"

"Who's Alice Mao?"

"I don't think you have what they want," says a soft voice at her side. "But I might have what you want."

"Relax, sweetie," says Mikki. "Have fun."

"That's one way of putting it. She's certainly not the sort of person you want to get on the wrong side of. But let me get you a drink. The watermelon Martinis are fabulous."

"Pretty girl," says Villanelle.

"And fabulously strong, I bet."

"Girl? Up to a point. That's Janie Chou, one of Alice Mao's ladyboys."

"She owns this club. In fact she owns this building. She's one of the richest women in Shanghai, thanks to the sex-trade."

"Obviously quite a businesswoman."

Villanelle looks into the pretty, upturned eyes of Janie Chou. "And what's that?"

As the other woman joins the crush at the small art deco bar, behind which an elegant young person is shaking cocktails, Villanelle allows herself to be swept along by a gesticulating crowd of young Chinese men, all designer-dressed to within an inch of their lives.

"Full girlfriend experience? Kissing on the mouth, lots of nice sucking and fucking, then afterwards I cook for you?"

"Perhaps not tonight. I've had a killing day."

Janie leans in close, so that Villanelle can smell the jasmine flowers in her hair. "I got crabs," she whispers.

"No, silly! In my fridge, not my lady-garden! Hairy crabs. Very expensive."

Villanelle raises an eyebrow.

"What are hairy crabs?"

Mikki approaches with two brimming Martini glasses and hands one to Villanelle, pointedly ignoring Janie. "Someone I want you to meet," she says, taking Villanelle's arm and steering her away.

"A local delicacy," says Mikki. "Unlike that little prostitute."

They shake hands, and Villanelle summons the details of her cover story. Astrid Fécamp, twenty-seven-year-old columnist for Bilan21, a French-language investment newsletter. Like all her legends, this one has been very carefully constructed. Should anyone care to investigate Mademoiselle Fécamp online, they will discover that she has been a contributing editor of Bilan21 for two years, and specialises in petrochemical futures.

She introduces Villanelle to a handsome young Malaysian man in a seersucker suit. "This is Howard," she says, clearly anxious for Villanelle's approval. "Howard, meet Astrid."

But Howard is too busy lavishing compliments on Mikki to concern himself with such minutiae. "Fuchsia!" he breathes, standing back to admire her Hervé Léger cocktail dress. "The perfect colour for you."

"So what do you do?" Villanelle asks. "Are you in the fashion business?"

"It's heaven," Mikki breathes. "There's a rock garden and an Evian ice fountain and Buddhist monks to align your chakras and do your hair."

Privately, Villanelle thinks the colour a disaster. Against her pale ivory complexion it makes Mikki look like Howard's mother. But perhaps that's what Howard likes.

"Sounds fabulous. I'm sure my chakras are all shot to fuck."

"Not as such. I have a concept spa in Xintiandi."

"Well then." Howard smiles. "You must come visit."

As soon as she can decently extract herself, Villanelle leaves them alone. Circulating, Martini glass in hand, she soon finds herself face to face with the sharks again. And, moments later, with Janie Chou.

"Come with me," Janie says, her features soft in the lunar glow of the tank. "Someone wanna meet you."

"Trust me, things do." Amusement touches the glass-green eyes. "Will you have some tea? One of those Martinis is quite enough, in my experience."

In a dim-lit alcove, a woman is sitting alone, scrolling through the messages on her phone. She's Eurasian, and when she looks up to dismiss Janie with a casual sweep of one hand, Villanelle sees that she has eyes of the palest glass-green.

Alice Mao frowns. "Do you now?"

Villanelle inclines her head in acceptance. From the woman's proprietorial manner she guesses that this is Alice Mao.

"It's… fun. Things could happen here."

"So. Do you like my club?"

"Financial forecasting. I write for an investors' newsletter."

"That would be nice. My name is Astrid, by the way."

"Come." Her slim hand takes Villanelle's.

"Who?"

"Janie's right," says the woman. "You're beautiful. Won't you sit down?"

"Yes." Villanelle holds her gaze. "I do."

"I've met a lot of finance people in my time, Astrid, and none of them is remotely like you."

"It suits you. Mine, as you know, is Alice. What is your occupation, Astrid?"

Alice glances at her phone. She stands, her midnight-blue dress rippling with the same underwater gleam as the sharks. "Follow me."

"On the basis of our brief acquaintance, I'd say you're rather like me."

Villanelle smiles, allowing Alice's cool regard to flood her veins. Something in the other woman's features, the way the taut line of her cheekbone softens into the curve of her chin, stirs her. She knows that such feelings are dangerous, but there are times when the secrecy and the almost feral caution with which she has to conduct her life become unbearable.

"So what am I like?"

She leads Villanelle to a door, and a lift. The noise and the music die, there's a dizzying ascent, and Villanelle follows Alice into a rooftop apartment as dimly lit as the club. There's a folding gold-leaf screen, and shadowy contemporary paintings on the walls, but the room is dominated by a dramatic expanse of plate-glass window. Far below them is the city, its sprawling glitter made vague by a shroud of smog.

"The whore of Asia. That's what they used to call Shanghai. And it's still true. This apartment, the club, this building… All paid for by sex. Tea?" She indicates a spotlit side table. "It's Silver Needle from Fuding Province. I think you'll like it."

Villanelle sips the pale infusion. It tastes of fragrant, rainswept hillsides.

"I could make you very rich," says Alice. "I have clients who would pay a great deal of money for a night with you."

"A hundred thousand," says Villanelle.

Villanelle looks out into the night. She can smell the other woman's scent, and her hair. "And you, Alice. What would you pay for me? Right here and now?"

Alice tilts her head thoughtfully, then steps round to face Villanelle. Green eyes meet grey. "For a hundred thousand kuai," she says, undoing the silk-covered button at Villanelle's collar, "I would expect a lot."

Villanelle nods, and stands there, unmoving, as Alice's fingers move down her qipao dress. She closes her eyes, feels the silk lifted from her shoulders, and her underwear removed. Naked, she feels the floor tilt beneath her feet. She tries to speak Alice's name but it comes out as Anna, and when she tries to whisper "fuck me," what she actually says is "kill me."

Alice looks at her, her smile unwavering. "Fifty thousand kuai."

Four days later Eve Polastri and Simon Mortimer step from the air-conditioned cool of the Pudong airport arrivals building into the 30-degree heat of the taxi rank. It's midnight. Exhaust-tainted humidity rolls over them like a wave. Eve feels her scalp moisten and her H&M cotton twinset wilt on her shoulders.

Freckled and scrappy-haired, her features free of make-up, Eve knows that she's not the sort of woman who gets noticed. Since landing an hour earlier the only person who's given her a second glance is the Chinese customs officer who checked her passport, perhaps struck by the quiet intensity of her gaze. Both she and Simon look older than their years. Their fellow British Airways travellers, if they've given the matter any thought at all, have assumed that they are a married couple.

Simon glances at her affectionately. She reminds him of a starling or a thrush, one of those birds that patrol the lawn with sharp eyes and stabbing beaks. The hunter-killers of the intelligence world, like those of the animal kingdom, often have drab plumage.

"I think you're very clever," her mother replied.

"I didn't know you spoke Mandarin," Eve says.

Simon runs a hand over his stubble-roughened jaw. "I did a year of it at university. If this guy starts a real conversation, I'm stuffed."

She misses him already.

He shrugged. "I didn't marry you for your cooking."

Flagging down a taxi, a green Volkswagen Santana, Simon gives the driver the address of their hotel.

Eve finds her own appearance mystifying. "Do you think I could be pretty?" she asked her mother, shortly before going up to Cambridge to read Criminology and Forensic Psychology.

"A bullshitter and a pervert."

"So does he know where the Sea Bird Hotel is?"

"Only when I want sex."

"You're such a bullshitter."

"I think so. His expression suggested he didn't think much of it."

"Let's see. Discreet was how Richard Edwards described it."

It took her husband, Niko, a Polish-born maths teacher, to tell Eve that she was beautiful. "Your eyes are like the Baltic Sea," he said, drawing a finger down her transparently pale cheek. "The colour of petrol."

Eve and Simon's visit is strictly non-official, so there's no one from the Shanghai MI6 station to meet them. Indeed, everything about their status is irregular. Since her recruitment by Edwards to investigate the Kedrin killing, an operation run strictly off-the-books, Eve has not contacted a single one of her former colleagues. Instead, day after day, week after week, she has made her way to the cramped and dingy office over Goodge Street tube station. There, with the long-suffering Simon, she has scrolled through file after classified file, staring at her computer screen until her head pounds and her eyes ache with tiredness, in the search for anything -- a whisper, an afterthought, the ghost of a suggestion -- that might lead her closer to the woman who murdered Viktor Kedrin.

And she's got nowhere. She's identified several high-profile political and criminal killings in which a woman is rumoured to have been involved, and a handful which she's almost certain were carried out by a female shooter. She has watched, more times than she can remember, the CCTV recording from Kedrin's London hotel in which his killer can be seen coming and going. But the images are smeared and indistinct, even when fully enhanced, and the figure's face is never visible.

When not scouring cyberspace, Eve has followed the real-world lines of inquiry presented by the Kedrin case. But every lead, no matter how initially promising, has brought her up against a smoothly impermeable barrier. There's no witness, no forensic evidence, no useful ballistics, no money or paper trail. At a certain point, everything just cuts out.

Despite this lack of progress, Eve has a sense of the woman she's hunting. The woman she sometimes calls Chernaya Roza -- Black Rose -- after the 9mm Russian hollowpoint ammunition used to kill Kedrin and his bodyguards. Eve thinks that her Black Rose is in her mid-twenties, highly intelligent, and a loner. She is audacious, cool under pressure, and supremely skilled at compartmentalising her emotions. In all probability she is a sociopath, wholly lacking in affect and conscience. She will have few or no friends, and such relationships as she forms will be overwhelmingly manipulative and sexual in nature. Killing, in all probability, will have become necessary to her, with each successful murder further proof of her untouchability.

It's less than twenty-four hours since Richard Edwards walked unannounced into the office over the tube station.

It took him less than five minutes to bring her up to speed on the demise of Lieutenant Colonel Zhang Lei. "Your brief," he told her, "is to make discreet contact with the MSS, the Chinese Ministry of State Security, and convey my assurances that the murder of Zhang was not sponsored, enabled or executed by us. Furthermore, you are to offer them any assistance they might need in investigating the murder, including sharing our suspicions about a female contract killer."

"Yes, Simon does. And very occasionally me. Sorry if it's not up to Vauxhall Cross standards. We've ordered some more vacuum cleaner bags."

"Does anyone ever clean this place?" he enquired, with vague distaste.

"Well, that's something to look forward to. And in the meantime…" He opened the briefcase at his feet, and took out two well-used passports and a sheaf of flight tickets and schedules. "You're going to China. Tonight. Someone's taken out the leader of their cyber-warfare team in Shanghai, and it's thought that the hit was carried out by a woman."

"Do I have a contact at the MSS?"

"Isn't he going to wonder why he's dealing with me, rather than one of the local station officers? Who are presumably already on the case."

"Yes. His name is Jin Qiang. I knew him in Moscow, when he was their head of station there, and he's a good man. Since then he and I have kept certain back-door channels open. He knows you're coming."

"So do we make contact with the MI6 station at all?"

Edwards stood, walked to the window, and peered through the grime at the traffic. "For safety's sake, we have to assume that the conspiracy to cover this woman's tracks has global reach. If she's killing people in Shanghai, they'll have people there. Possibly our people. So you've got to keep clear of them. We can't afford to trust anyone."

"How much can I tell the MSS guy?"

"He'll guess there are sensitivities. Reasons why you can't go in under official cover."

"Jin Qiang? As far as our hitwoman goes, you've got nothing to lose by giving him everything you've got." He drained his coffee, and dropped the paper cup into the bin. "We need to catch her, he needs to catch her."

"Hello, Simon. Good morning."

The door swung open. "You know, I'm convinced Goodge Street station's a portal to hell," said Simon, shrugging his computer bag from his shoulders onto his desk. "I've just had such a Buffy moment…" He froze. "Oh, hello, Richard."

"We're going to Shanghai," said Eve, and wondered what on earth she was going to tell Niko.

And it is. They're approaching the Nanpu Bridge, with vast office blocks to right and left of them, their numberless windows pinpricks of gold against the bruised purple of the sky. And suddenly Eve's tiredness evaporates, and she's light-headed with the novelty of it all. Everything's about money and profit. You can see it in the soaring high-rises, smell it in the diesel fumes, taste it on the night air. The hunger. The high stakes and the huge returns. The unbridled sense that more is more.

"Look at this," Simon says, lowering the window of the taxi and flooding it with the warm night. "It's extraordinary."

It's an impression that's confirmed as they cross the bridge. Below them, boats festooned with tiny lights ply the dark expanse of the river. To their right, in floodlit splendour, waits the Bund.

"She's out there," Eve murmurs. "Our Black Rose."

"No. To be honest with you, I can't."

"How d'you feel?" Eve asks him.

He leans forward, his buff linen jacket folded on his lap. "I'm not sure. Things have got very strange recently."

It's only when she's in her room, a functional space whose off-white walls are decorated with a single out-of-date calendar, that she allows herself to think about Niko. The phone call after Edwards left the office was horrible. It would have been easy enough to think up a cover story, but she couldn't bring herself to lie, and told Niko simply that she had to go away for a few days. He listened, said "I see," and hung up. He has no idea where she is, or when she will be coming home. Eve stares out of the window. There's a road, and beyond it the dark gleam of water. A cluster of houseboats, showing dim lights.

"Assuming it was. Why would she stick around?"

"We don't know for certain that it was her who killed the hacker."

"Oh, it was her all right."

"For me, Simon. She's waiting for me."

"Now you're actually starting to sound mad. I'm putting it down to jet lag."

He closes his eyes. Five minutes later they're at the hotel.

"You wait."

"Can't you guess?"

Villanelle nods. The two of them are sitting in the tenth-floor apartment in the French Concession. On the table between them is a bottle of Tibet Glacier mineral water, two glasses, and a packet of Kosmos cigarettes.

"Which means that they're not here officially," Konstantin continues. "The Sea Bird is dirt cheap, by Shanghai standards."

"They're staying at the Sea Bird Hotel on Suzhou Creek," says Konstantin. "They got in last night."

Villanelle stares out at the pale glare of the sky. "So why do you think they've come?"

She loves Niko, and she's hurting him deeply, and this is especially agonising because, for all his wisdom and experience, she can't help thinking of herself as his protector. She's guarding him from the truth about herself. From the side of her that he knows exists, but that he chooses not to acknowledge. The side of her that is utterly absorbed by the woman she is hunting, and the dark, refracted world in which she exists.

"We both know why they've come. The Polastri woman was asking questions in London after Kedrin's death, as I told you at the time. If she's here, it's because she's made the right connections."

"I can't do that."

His expression hardens. "This is not how I want things to be between us, Villanelle. I don't want to have to negotiate every decision."

"Which means that she's smart. Or lucky. And that I need to get a close look at her."

"No. That would be reckless. I'm pretty sure Polastri's got no real clue what's going on, but that doesn't mean she's not dangerous. Leave her to me, and go back to Paris. We need to wind this operation up. The hacker's dead, and you need to disappear."

"I know you don't. You want me to be your killer doll. Wind me up, point me at the target, bang bang and back in my box." She looks him in the eye. "Sorry, but that's not how I function these days."

"Like a thinking, feeling human being."

"I see. So how do you function, exactly?"

He looks away. "Please, Villanelle, don't talk to me about feelings. You're better than that. We're better than that."

"Are we?"

"Yes. We see the world for what it is. A place where there's only one law: survival. You survive very comfortably, do you not?"

"Maybe."

She looks away irritably. "That I'm never completely safe. And that I should never fully trust anyone."

"Exactly. Remember that, and you're fine. Forget it and you're fucked." He reaches for the cigarettes. "Forget it and we're all fucked."

She looks at him. The acrid tobacco smell reminds her of their earliest days together. In Russia, he must have smoked at least a packet a day. "So who's going to shoot me? Eve Polastri? I don't think so."

"Worried about your health?" Konstantin asks, lighting a Kosmos. "I'd have thought a bullet in the back of the head was a more pressing concern."

"And why's that? Because give or take a couple of reckless incidents, you've obeyed the rules. What did I tell you in London?"

Frowning, Villanelle walks to the plate-glass door to the balcony and pulls it open. Humid air fills the room.

"Trust me, Villanelle, her people will kill you without a second thought. One word from Polastri to Edwards, and MI6 will send in an E Squadron action team. Which is why you have to get out, now. Shanghai's a big place if you're Han Chinese, but it's a very small town if you're not. You could run into her anywhere."

She does so, and for a long time he's silent. "It's too dangerous," he says eventually. "Too many variables. We could end up attracting exactly the wrong kind of attention."

She sits down on her unmade hotel bed. The room is small, with worn bamboo furniture and a distant view of the creek. Underwear is visible in Eve's open suitcase, and she wishes they'd agreed to meet downstairs.

"Shit," says Eve, staring at her phone. "That's a bad start."

"Really?" He exhales cigarette smoke, which drifts away on the warm breeze. "And would you kindly tell me how?"

"I won't, don't worry. But I do have a way of getting to her. And perhaps of finding out what she knows."

"It's too dangerous," he repeats.

He stands up. Walks out onto the balcony. Finishes his cigarette, taking his time, and flicks the end out into space. "If we do it," he says. "You stay out of sight. I make the play. Agreed?"

"You once told me that kind of operation was a speciality of yours." She looks at him speculatively. "Fear, sex and money, you said. The three great persuaders."

She grins, her expression fierce.

"Tell me," says Simon.

She looks away. "We might never get this chance again. We can't afford not to take it."

DCI Gary Hurst is the senior investigating officer on the Viktor Kedrin case. He has been following up a loose end which, just conceivably, could indicate an error on the part of those who set up Kedrin's murder. It seems that the theft of the card used by Lucy Drake to check into the hotel was reported to the police by Julia Fanin, but not to her bank. As a consequence, the hotel registration went through unchecked.

This discrepancy puzzled Hurst, especially when Fanin insisted that she had rung her bank's Lost and Stolen Card number, a claim validated by her mobile phone records. It turns out that the bank's credit-card support services are outsourced to a call-centre company based near Swindon, in the south-west of England, and Hurst's investigation has concluded that one of the company's employees unfroze the card after it was reported missing, so that it remained usable. Thousands of pounds worth of clothes, flights and hotel bills were then charged to the account over a two-week period, at the end of which the expenditure stopped dead. Which is where the investigation has stalled. Hurst's text reads:

"It's Hurst." She hands him the phone. "The Fanin credit card trail's gone dead."

In the online catalogue, Eve's mint-green shift dress was described as a "chic, summery office staple," but catching sight of herself in a mirror in the lift, she senses that she's striking the wrong note. The dress is sleeveless and she's cut herself shaving -- her armpit still stings quite badly -- so somehow she has to conduct a vital meeting with a senior officer of the Chinese Ministry of State Security without ever raising her right arm.

"And even if by some miracle he gets a result, it's a dead cert we'd just hit another cut-out," says Simon, returning Eve's phone.

Right now working thru 90+ employees who might have taken JF's call. But relevant records deleted so not confident of a result.

She slips it into her bag. "Let's go and see Jin Qiang. The taxi should be waiting downstairs."

Opened in 2009, the first new building on the Bund for seventy years, the Peninsula Hotel is dauntingly grand. The lobby is pillared art deco, a tone-poem in ivory and old gold. The carpets are vast, the conversation muted. White-uniformed bellboys hurry discreetly between the vast reception desk and the near-silent lifts.

"Mrs. Polastri, Mr. Mortimer. This is a great pleasure."

Jin Qiang is alone in the suite. It's vast, soft-lit and restfully luxurious. Sky-blue curtains frame a view of the river, and more distantly the skyscrapers of Pudong.

"Thank you for agreeing to see us," says Eve, as she and Simon lower themselves into silk-upholstered armchairs.

"I have most affectionate memories of Richard Edwards. I trust he's in good health?"

For some minutes, the niceties are observed on both sides. Jin is a quietly spoken figure in a dove-grey suit. He speaks English with a faint American accent. At intervals a look of refined melancholy touches his features, as if he's saddened by the vagaries of human behaviour.

"The murder of Zhang Lei," Eve begins.

"We wish to convey our assurances that this action was not sponsored, executed or in any way enabled by agents of the British government," Eve says. "We have had our differences with your ministry, particularly concerning the activities of the individuals calling themselves the White Dragon. A unit, we have reason to believe, of the Chinese military. But this is not the way we would choose to resolve those differences."

"Yes, indeed." He steeples his long, manicured fingers.

Jin smiles. "Mrs. Polastri, you are mistaken in thinking that the White Dragon group is part of the Chinese People's Liberation Army. They, and others like them, are just mischief-makers, acting without reference to anyone."

Eve inclines her head diplomatically. This, she knows, is the official line on all cyber-attacks originating in China.

"We're here in Shanghai to assist in any way we can," says Simon. "Especially with reference to the killer of Lieutenant Colonel Zhang."

"Of course. My apologies. But we understand that Richard Edwards has communicated to you our suspicions concerning a female assassin?"

"He was, I'm afraid, just plain Mr. Zhang."

Eve leans forward in her chair. "Let me cut to the chase. We believe that the woman who killed Kedrin also killed Zhang Lei. We believe she is not acting alone, but on behalf of an organisation of considerable reach and power."

"That is indeed cutting to the chase, Mrs. Polastri. May I ask what Zhang Lei and Viktor Kedrin had in common, that they should both be… eliminated by this organisation?"

"He has. And I'm aware of the circumstances surrounding the death of Viktor Kedrin."

"Please do."

"At this stage it's hard to say. But I would repeat that neither we nor our American colleagues had any hand in the death of Zhang Lei. Nor that of Viktor Kedrin."

Eve is suddenly conscious of the cut under her arm. For a ghastly moment she wonders if she has left a bloodstain on the silk upholstery of her chair. "May I be frank with you?" she asks.

Jin folds his hands in his lap. "I must accept your assurances."

"Richard Edwards's belief, which we share, is that a covert organisation -- as yet unidentified -- is committing these murders. We don't know their purpose or agenda. We don't know who they are, or how many. But we suspect that they have people placed in our own organisation and also in MI5, for whom I used to work. And almost certainly in other intelligence services."

Jin frowns. "I'm not sure how I can help you."

Eve feels the meeting slipping from her grasp. "Our only way forward, as things stand, is to follow the money. Is there anyone in the Western security services, Mr. Jin, whom you know or suspect to be in the pay of an organisation such as I have described?"

Exasperated, Alice rolls onto her stomach. "Please. Just come to bed?"

"I have to go shopping."

"Have you seen my black cardigan?" Villanelle asks. "The Annabel Lee one, with the pearl buttons?"

"I'm sure I left it here somewhere," Villanelle murmurs.

Jin's features remain impassive. "Perhaps we might order some tea," he suggests.

Silence swirls dizzyingly around her. She senses Simon's shock at the impropriety of her question.

In answer, Alice Mao groans. She's lying on her bed opposite a young man with chiselled features and a gym-toned body which gleams like oiled teak. Both of them are naked. Beneath the silk sheet, the man's hand is moving rhythmically between Alice's legs. It's half past two in the afternoon.

Villanelle knows Ken's story, because Alice has told it to her. How he was a student at Hong Kong University, completing an MA dissertation on the late poetry of Sylvia Plath, when he was talent-spotted in a hotel steam room. How he became Ken Hung, the most famous porn star in China.

"Now?"

Villanelle shrugs.

"Ken's very much in demand, you know," Alice says. "He's doing us a huge favour, fitting us in like this."

Alice gasps. "Oh my goodness, it's just like in the films. Bigger, even. Sweetie, at least have a little stroke."

As if on cue, Ken throws back the sheets. "Ladies, we have wood!"

An hour later, Villanelle is strolling down one of the many aisles of Putua Parlour, noting the positioning of the CCTV cameras. It's a warehouse store for the restaurant trade, offering every imaginable appliance and vessel. Shelf after shelf is piled high with pans, skillets, steamers, hotpots, baking dishes and gleaming tinware. There are elaborate cake stands, fantastical jelly-moulds, and an entire aisle of woks. Tiny woks for flash-frying individual prawns, jacuzzi-sized woks capacious enough for a whole ox.

"Sorry, but I really don't want that thing anywhere near me. I just want my black cardigan." Villanelle frowns. "You don't happen to know somewhere I can buy nice kitchen stuff, do you?"

"You could try Putua Parlour on Changhua Lu," says Ken, complacently regarding the most famous penis in China. "I get all my bakeware there. I'm a big Nigella fan."

In the last aisle, Villanelle finds what she's looking for. Cleavers. Fine-bladed cleavers for slicing and dicing, heavy bone-choppers for hacking and dismembering. Her eye alights on a chukabocho, a locally made cleaver with a 25oz carbon-steel blade and a tiger-maple handle. It feels good in her hand. Two minutes later she checks out, paying for a dozen cocktail glasses and several sets of paper umbrellas. Somehow, unseen by the CCTV cameras, the chukabocho has made its way to the bottom of her shoulder bag.

The place has only a handful of customers. There's a young couple quietly arguing about kebab-skewers, a harassed-looking man loading a trolley with bamboo dim-sum steamers, and an elderly woman muttering to herself as she picks through the melon-ballers.

"This is not a date. This is an appointment with the head of the Chinese Secret Service."

"OK, I admit it," says Eve. "I'm nervous."

"You've been on dates before, haven't you?"

"If you say so. I think he fancies you."

"Simon, please. You're not helping. I feel very uncomfortable in this dress. And these shoes. I can hardly walk."

"Well, be good. I'm going to wait downstairs."

"I thought I might take a stroll down the Bund." He shrugs. "Perhaps look in somewhere for a cocktail."

"He's picking me up downstairs in ten minutes. What are your plans?"

"You look adorable. When are you meeting him?"

"Have fun."

She throws him a sardonic glance, and teetering a little in her new Lilian Zhang cocktail dress and Mary Ching stilettos -- the prospect of submitting the expenses claim makes her blood run cold -- runs a last check in the mirror. She looks, she's forced to admit, pretty good. The hotel hairdresser's even magicked her mousy hair into something resembling a French roll.

"No! Now go."

"You don't think the make-up's too much?"

The invitation came as a surprise, to say the least. The meeting in the Peninsula suite had more or less stalled after Eve's questioning of Jin Qiang. Spies, even among themselves, are highly disinclined to admit that they actively engage in spying. Following a further hour of discussion of the murder of Zhang Lei, in the course of which Eve handed over a prepared dossier about the investigation of the Kedrin murder, Jin brought the meeting to a halt and ushered her and Simon down to the lobby.

There, amid the art deco grandeur, the same cast of business types appeared to be engaged in the same muted conversations. As they shook hands beneath the pillared portico, Jin hesitated. "Mrs. Polastri, I'd very much like to show you something of Shanghai. Are you by any chance free this evening?"

"I am," she said, surprised.

She opened her mouth to thank him, but he was already gliding soundlessly away.

He arrives at 8 p. m. precisely. He's on a scooter, wearing a sharp black suit and open-necked white shirt, and looks a very different man from the cautious intelligence officer Eve met just hours earlier.

"Excellent. I'll call for you at your hotel at eight o'clock."

"Mrs. Polastri, you look… spectacular." With a courtly smile he hands her a tiny bouquet of fresh violets, tied with a silk ribbon.

Eve is enchanted, and thinking of Niko teaching GCSE maths to a class of bored teenagers half a world away, she feels a stab of guilt. Thanking Jin, she wraps the dewy violets in a tissue and places them in her bag.

"Ready." She arranges herself side-saddle, as she's seen Shanghainese women do.

"Ready?" he asks, passing her a helmet.

They swing out into the traffic, and onto East Nanjing Road. The thoroughfare, one of Shanghai's busiest, is gridlocked and exhaust-choked. Jin weaves the scooter deftly between the crawling vehicles and comes to a halt at a red light.

As Eve sits there, the scooter burbling beneath her, she catches sight of a striking figure walking up the pavement towards her. A young woman, poised and slender, in jeans and a black, pearl-buttoned cardigan. Dark blonde hair slicked back from fine, sharp-cut features. A subtle, sensual twist to the mouth.

Eve watches her for a moment. Has she seen that face before, or is it just déjà vu? As if sensing her stare, the woman glances back. She's beautiful, in the way that a bird of prey is beautiful, but never has Eve encountered a gaze of such inhuman blankness. When the lights change, and the scooter lurches forward, the temperature seems to have dropped a degree or two.

"You like dancing?"

She smiles. "You sound as if you'd like those days to return."

She accompanies him into a foyer hung with sepia photographs, and from there into a small lift that conveys them unhurriedly to the fourth floor. The dance hall is like a music box in gilt and red plush. On the stage, a middle-aged singer in a floor-length evening dress is delivering a smoky-voiced version of "Bye Bye Blackbird," as a dozen or so couples gravely quickstep around the cantilevered dance floor.

Jin leads Eve to a side table in a booth, and orders Coca-Cola for both of them.

Five minutes later they draw up at an intersection, outside a grand art deco building topped by a cascading neon spire. Coloured lights course up and down its antique facade. Above the portico, the word Paramount blazes into the twilight.

"I… yes," Eve replies. "I do, actually."

"The Paramount is a famous landmark from the nineteen-thirties. This is where everyone came to dance. Gangsters, high society, beautiful women…"

He locks the scooter. "They were interesting times. But then so are these. Come."

"Business first," she agrees, sipping the sugary drink. A couple glides wordlessly past them.

"Business first?" he asks.

"What I tell you, you never repeat, OK?"

She shakes her head. "This conversation never took place. We talked about dancing. About nightlife in Old Shanghai."

Eve notes that Jin is, in effect, admitting that Zhang Lei was working for the state.

He moves closer to her on the banquette, and inclines his head towards hers. "Our late friend, as you know, was killed in an establishment in the Old City. He was a surgery fetishist. A masochist. We knew about this. He visited the place every six weeks or so, and paid a professional sex worker to simulate… various medical procedures. He was discreet about these visits; his colleagues knew nothing about them."

"But not discreet enough to escape your department's notice, evidently."

"Evidently."

"So we are either looking at an organisation able to mount an extensive and long-term surveillance operation…" She hesitates. "Or one with access to information acquired by your department."

"Yes. That's right."

Jin frowns. "Certainly the former. Just conceivably the latter."

Eve nods slowly. "Either way, a sophisticated organisation with a long reach."

"Yes. And I don't believe it was the British, or the Americans. The economic consequences of discovery would be…"

"Right now, not really, although one can never discount a Russian connection, especially if, as you suggest, the same organisation is responsible for the death of Viktor Kedrin. So we're trying very hard to find out more about the woman they sent. We know that she entered by the back stairway, overpowered the sex worker who calls herself Nurse Wu, who remembers nothing beyond the fact that her attacker was a woman, and then eliminated our friend by means of carbon monoxide poisoning."

"You're sure that was the cause of death? It couldn't have been an accident on the part of this nurse person? After all, she wasn't qualified to administer surgical gas or anything of the sort, surely."

"Catastrophic?" Eve suggests.

"So do you have any other ideas for who might be responsible?"

"Very sure. And there's a man who has a food stall on Dangfeng Road opposite the backstairs exit. He knows what the building is, and that only men come out of that door. So when he saw a woman, he remembered her."

"Cherry-red lips and skin?"

"The only gas she ever gave her 'patients' was pure oxygen. We tested all the tanks there. And as it happens, as well as being a part-time sex worker she was also a trained nurse, who worked in a private medical facility in Pudong. So she knew what she was doing. And the symptoms of carbon monoxide poisoning are unmistakable."

"Does he remember what she looked like?"

"But no sign of a CO tank, or canister?"

"She's sure about this?"

"No, he said all Westerners look the same to him. Baseball cap is all he remembers. New York Yankees."

"She remembers the feel of a woman's breasts against her back when she was grabbed. And the hand that went over her mouth was strong, she said, but not a man's hand."

"No, the killer took it away with her."

"Exactly. The pathologist was in no doubt."

"And what makes this Wu person so sure that her attacker was a woman?"

"Very much so. My service is very grateful, Mrs. Polastri. We showed the images of the woman in the hotel to people who work on Dangfeng Road, and several said they might have seen her that day."

"Our killer's very good at being invisible. Has the material on the Kedrin murder been any use?"

"But no one was sure?"

"No. Unfortunately."

"We are grateful, nevertheless. And of course we're checking against visas, and watching all border points. We're talking to people in all the hotels, clubs, and restaurants that a foreigner might visit."

"I'm sure you're doing everything that could be done."

"They're very poor quality images. And you can't see her face. So I'm not surprised."

"We are." Jin smiles. "And now, would you like to dance?"

Dragon-fruit Martini in hand, Simon makes his way towards one of the Star Bar's few unoccupied seats, which appears to be upholstered in zebra-skin. "Boss Ass Bitch" by Nicki Minaj is pumping from concealed speakers, and the place is filling fast. Simon is wearing Diesel jeans and a cotton jacket, and the Lonely Planet guide from which he chose the bar ("a watering-hole popular with the cashed-up expat crowd") is weighing down his right-hand pocket.

He would never admit it to Eve, and obviously she's his head of section and it's Jin Qiang's turf, but he's not exactly happy that she's swanned off without him for a night on the town with Jin. It's not as if she's not going to tell him everything that's discussed when she gets back, but it would have been nice if she'd, at the very least, suggested that he come along. He's very fond of Eve in an exasperated, semi-protective sort of way (her fashion sense, oh my God) and he certainly isn't one of those sad haters who can't deal with a female boss, but she can be pretty insensitive at times, despite her undoubtedly high-wattage intellect.

Lowering himself into the zebra-skin chair with an insouciance he doesn't feel, Simon takes a deep hit of his drink. The Star Bar's decor is preposterous, even for Shanghai. The emerald-green stingray-skin walls are hung with sub-pornographic paintings, the fireplace is black marble, a vast Fortuny-style chandelier glows overhead. The overall effect is absurd, alluring, vaguely satanic.

"I suppose I am, yes."

"All alone?"

At first Simon takes no notice, not believing that the question has been addressed to him. Then the slight, dark-haired figure at his side swims into focus. He takes in the mischievous upturned eyes, the dimpled grin, the sharp little teeth.

The Martini is volcanically strong, caressing Simon's taste buds with sugary top notes before drenching his cerebellum in iced Berry Bros. No 3 gin. Half-closing his eyes, he feels himself wreathed in flavour. Juniper, a hint of grapefruit, and that sexy, suggestive dragon-fruit sweetness. Fuck me, he murmurs, his brain clouding with pleasure. That hits the spot. Around him drift expensively dressed revellers. Friends, office colleagues, lovers… Why is it always, always like this? Everyone else at ease, having the time of their overpaid lives, while he's on the outside, face pressed to the glass, invisible.

"You new here then. I think I remember if I see you before."

"My name's Simon. I got in a couple of days ago." He gazes at her, marvelling at the soft swell of her breasts in the lilac crop-top, the trim little stomach, the skinny jeans and pretty, strappy shoes. She is, without question, the most beautiful creature he's ever seen.

"There's a film I love, made here in Shanghai in the 1930s, called The Goddess. A silent film. Very sad. Very beautiful and tragic actress Ruan Lingyu. She shows great emotion in her face, and in her movements."

"Are you familiar with Chinese cinema, Mrs. Polastri?"

"I know. But also elegance… glamour."

"No, I'm afraid not."

"You sound like a romantic, Mr. Jin?"

Jin Qiang is a superb dancer. To the swooping, shivering strains of "Moon River," he waltzes Eve expertly round the floor, one hand lightly holding hers, the other against the bare flesh of her back, guiding her. Despite their price, she's glad she bought the cocktail dress and the shoes.

"So would you like to have lived in the 1930s?" she asks him.

"It was a time of great inequality. Great hardship for many."

"She killed herself, aged twenty-four. She was unhappy in love."

"Oh my goodness, that is tragic."

"She sounds wonderful."

"Hi," she says. "I'm Janie."

"Indeed. Today, I don't think many people in Shanghai would kill themselves for love. Too busy making money."

"I'm sorry you're stuck with me. With my two left feet."

"Like spies?" Eve suggests.

"There are a few of us left. But we operate in secret."

They both smile, and "Moon River" comes to a close. Ice-blue neon flickers round the stage, and the singer segues into "The Girl from Ipanema."

"You have two left feet? Really?"

"The foxtrot," says Jin. "My favourite."

"It's an expression. It means I'm a bit clumsy."

"That is something I would never say about you, Mrs. Polastri."

Half an hour later they're on the scooter again, careering through streets vivid with neon. Eve is enjoying herself. Jin is a man of many interests. Hunan food, early Chinese cinema, and post-punk music among them. His favourite band, he tells her, is Gang of Four. "With that name, how could I resist them?" At the same time Eve recognises that for all the wry surface charm, there is a steeliness to Jin Qiang. In a tight corner, this man would make the hard choice, take the pragmatic decision.

They come to a halt outside an unprepossessing-looking establishment on a side street. As Jin opens the door, oily steam gusts into their faces. The place is crammed, and noise levels are deafening. Everyone seems to be shouting, and there's a continuous clattering of pans and woks from the kitchen. Standing in the doorway, Eve is pushed roughly out of the way by a departing customer. Taking her arm, Jin steers her towards the small counter. A tiny, ancient woman in a greasy apron appears and directs them to a plastic-topped table. Narrowing her eyes at Eve, she screeches at Jin in Mandarin.

She knows what he means. Given the noise levels, audio surveillance would be impossible here.

"I understand," says Eve quietly. "And thank you. We will not let you down."

"I'm trusting you with my career, Mrs. Polastri. If you are right, and we face a common enemy -- this organisation you speak of -- we should work together. But I doubt Beijing would see it that way, so…"

"I have something for you," he says, and below the level of the table, places a sealed envelope on her lap.

She laughs. "You're going to have to help me with the menu."

Simon knows, straight away. Janie's hands, perhaps. Something in the set of her cheekbones and her mouth. But it doesn't matter. He's lost.

"Not bad," he agrees. "And private."

In the end they settle for spicy skewered shrimps and cumin-crusted ribs washed down with cold beer. It's delicious, among the best food Eve has ever tasted. "Thank you," she says, when she can eat no more. "That was fantastic."

She doesn't move or speak.

"She says I'm a very naughty boy," he tells Eve. "She thinks I've picked you up."

He inspects the streamers pinned to the walls. "How about bullfrog in rice wine?"

There was a girl at university, an Eng Lit student who played in a ukelele band. She and Simon slept together intermittently, but he was never quite sure what she expected from him, and eventually the relationship faded into a friendship with which they were both more comfortable. He wondered, vaguely, if he was gay, and in the spirit of experiment, allowed himself to be seduced by his male tutor, a mediaevalist with a penchant for Gregorian plainchant and spanking. That didn't really work out either, and Simon decided to let the whole sex thing slide, and to concentrate on his studies. He left with a first-class degree and an unfocused sense of longing. For what or for whom, he didn't know. For almost a year he lived at home, celibate and unemployed. Then one day, almost as a joke, a friend emailed him a link to MI5's recruitment page. From day one, the secret world felt like home.

She tells him she works for a child-minding agency. That she lives in a one-bedroom flat in Jingan, near the Art Theatre. As they talk she gazes at him. No one's ever looked at him like this. The soft, unblinking stare. The long brown eyes fixed patiently on his.

Two dragon-fruit Martinis later (Sprite for her, touchingly), they're dancing. The playlist is commercial pop, and Janie sings along to every track. Simon's not much of a dancer, but the floor's too crowded to do more than shuffle and nod. The tempo slows, and he places his hands on her hips, feeling their gentle sway, inhaling the scent of the jasmine blooms pinned to her upswept hair. Intoxicated, he draws her towards him, and she lays her head on his shoulder. Through his jacket, which he dares not remove for fear that it will be stolen, he feels the unyielding pressure of her breasts. His heart pounding, he touches his lips to the soft tendrils of hair at her temple. He doesn't think she'll sense this but she does, and her face tilts up to his, her lips parted.

He's told Janie that he's "here on business," and this seems to satisfy her. She asks him about his likes and dislikes. About movies he's seen, about pop videos, boy-bands, celebrities, shopping and fashion. In anyone else this bubblegum worldview would be exasperating. In Janie, it's enchanting.

He knows. He can feel the evidence swelling against his thigh.

Kissing her, feeling the sugary flicker of her tongue, he feels a lightness of being so intense he wonders if he's going to pass out. She moves her mouth across his cheek, nips his earlobe with her little cat's teeth. "You know I wasn't always a girl," she whispers.

Eve stares at the paper for a moment, trying to divine its importance, before replacing it in its envelope and locking it in her briefcase. Jin, she knows, is returning to Beijing tomorrow. The investigation into Zhang Lei's murder will continue, but there is no more that she can contribute. It's time for her and Simon to fly back to London, report to Richard Edwards, and investigate the lead that Jin has given her at such personal risk. She also needs, urgently, to make things right with Niko. It will be good to be home again, but part of her will miss Shanghai and its luxurious strangeness, its myriad scents and colours. And part of her, she's forced to admit, will miss Jin Qiang.

In her room, she takes out the envelope that Jin has given her. Inside is a single A4 page, which appears to be a printout of a transfer of funds between two international banks. The banks and account-holders are identified only by number codes. The sum in question is a little over ￡17 million.

"It's fine, Janie," he says. "Really, it's fine."

Back at the Sea Bird Hotel, Eve knocks on Simon's door, but he's still out. And having a good time, she hopes. He's a good friend and colleague, but he definitely needs to loosen up.

Drifting between wakefulness and dream, Simon knows a peace that he's never thought possible. Beside him, Janie turns, and raises her arms sleepily above her head. "Promise you like me?" she murmurs. "Not just using for sex? Wham-bam, then bye-bye Janie?"

In bed, she reviews the evening moment by moment, and in particular the dancing. The open window admits a faint breeze, and with it the corrupt tang of Suzhou Creek. It takes her some time to fall asleep.

"Like you?" he wants to tell her. "I love you. You're everything I've ever wanted. I'd give up my work, my country, everything I know and believe in, to share my life with you." But he says nothing, and instead plants slow kisses on the pale curve of her left breast. She watches him for a moment, and then, eyelids fluttering, she plucks at her nipples and they begin again.

Some time later Simon wakes, and through half-closed eyes sees her tiptoeing round the room, slim-hipped and naked, long hair swinging round her shoulders. When she first brought him here, he was touched by the modesty of the place. The cheap chest of drawers and dressing table, the Barbie-pink curtains and bedspread, the Hello Kitty poster on the wall. Now she touches his clothes, running her fingers over the jacket he's slung over the single chair. A slim hand disappears, and an instant later reappears holding his phone. She looks at it admiringly for a couple of seconds, and replaces it. The action touches Simon, who guesses that such an article is way beyond her budget.

Then, with great speed, she dresses herself, pulling on white knickers, jeans and a T-shirt, and pushing her feet into a pair of trainers. As she tip-toes towards Simon, he pretends to be asleep. She leans over him for a moment, so close that he can hear her breath, and then backs soundlessly away. Opening his eyes, he sees her dip her hand back into his jacket, take the phone, and hurry from the room.

Simon lies there for a moment, too shocked to move. Then he leaps from the bed, and lifts the rattan blind. He catches a fleeting glimpse of Janie beneath a street light, moving fast, and then she's gone.

He pulls his clothes on, sick with dread, and races down the narrow staircase to the street. It's rained while they've been in bed, and the air is charged with the smell of the wet streets. Simon is soon breathless and footsore, his shirt clammy with sweat.

But there she is ahead, and he drives himself after her. What the fuck? What the actual fuck? Has he just fallen hook, line and sinker for the oldest scam in the book? If Eve and Richard Edwards discover any of this, any of it, he's finished. Forget the sheer, gobsmacking unprofessionalism, the humiliation would be off the scale. Honey-trapped by a nightclub tranny. A chick with a dick. What a 24-carat twat he's going to look.

There's just one chance. If he can get to her, and somehow get his phone back… Perhaps, just perhaps, Janie's exactly what she says she is. Perhaps she simply couldn't resist the chance to make a few bucks by stealing a high-tech foreign phone. Please, he prays, as he dodges and weaves through the crowds, dragging the muggy night air into his lungs, please let that be the case. Let it be something forgivable. Let me get back with Janie. Because he knows that as long as he lives, he will never experience anything like the dreamy bliss of their intertwined limbs.

The streets are narrowing now, and the crowds thinning. Instead of street lights, there are loops of low-wattage bulbs strung between half-completed dwellings. Incurious faces look up from beneath sagging awnings and watch him as he passes. There are still a few food stalls operating, a few woks sizzling over charcoal fires, and Simon slows to avoid a rickety table supporting a plastic bowl of writhing, living creatures.

Janie's still about forty yards ahead -- Christ, she can move -- and now they're in some kind of new-build estate. Rendered-brick housing blocks intersected by a grid of unlit lanes. The area's almost deserted, and if she turns now, she'll see him.

Too wretched to be afraid, he forces himself to note every detail of the man's appearance. There's a brief conversation, and then he and Janie vanish into the building together. After a minute, Simon warily approaches the entrance, looking for a name or a number. There doesn't appear to be either, but he's confident he will be able to find the place again.

At the entrance to one of the buildings she presses a buzzer. After perhaps half a minute, a figure steps into the dim pool of light, and Simon knows immediately that the scenario is infinitely worse than any he's imagined. The man's not Chinese. He looks Russian or Eastern European, and he's got hardcore intelligence operative written all over him. Even at a distance, he radiates a pitiless authority. I'm fucked, Simon tells himself, as Janie hands the man the MI6-issue phone. I'm totally and utterly fucked.

Shrinking into the shadows Simon checks his watch. It's almost 2 a. m. The temptation to call out to Janie is agonising, overwhelming. But he has to know the truth.

The voice is coming from the unlit lane on his left. Heart pounding, he takes half-a-dozen tentative steps, senses movement in the darkness, catches an incongruous hint of French perfume on the night air.

Briefly, he considers simply telling Eve that he has lost his phone, that it's been stolen, and not saying anything about Janie. But he knows that it's not in him to lie. He'll tell her everything and offer his resignation, effective immediately. Perhaps she'll accept it and send him back to London for what will undoubtedly be a highly unpleasant debriefing by Richard Edwards. Perhaps -- and his heart leaps sadly at the prospect -- they'll decide to keep him in play. Feed him back to Janie to find out who's running her.

"Simon, over here."

He's fifty metres from the building when he hears his name called.

He stops, sure that he's mistaken. But there it is again, low and clear on the warm, damp air. Is it Janie? How could it be? As far as she's concerned, he's asleep in her flat.

"Who's there?" he asks, his voice unsteady.

Ten minutes later she spots a battered Kymco scooter parked at the foot of an apartment block. Disabling the ignition lock and kick-starting the engine, she heads northwards, keeping to the narrower roads, until she reaches Nan Suzhou Lu, where she drops the plastic bag into the dark swirl of the creek. It's a beautiful night -- the sky purple, the city dim gold -- and Villanelle feels vibrantly, thrillingly alive. Killing the English spy has restored something in her. The Zhang Lei action had its professional satisfactions, but the moment itself lacked impact. Taking out Simon Mortimer was a return to first principles. A violent, artistic kill. The chukabocho, weighed in the hand, was not so very different from the Spetsnaz machete her father taught her to use when she was a teenager. Unwieldy to begin with, but a lethal thing when correctly deployed.

Rising on her toes like a matador, eyes demonic, Villanelle sidesteps the black swathe of blood thrown from the falling body. Simon's limbs shudder, a bubbling sound issues from his neck, and as he dies Villanelle feels a rush of feeling so intense, so icily numbing, it almost brings her to her knees. She crouches there for a moment, waves of sensation coursing through her. Then, wrenching the chukabocho free of the corpse and dropping it into a plastic shopping bag, followed by her bloodied surgical gloves, she walks swiftly away.

He has a momentary impression of a figure exploding from the shadows, of the whirling arc of the chukabocho, and then the carbon steel blade chops through his throat with such force that his head is almost severed.

Villanelle is about to head southwards towards the French Concession when a thought occurs to her. Within minutes, the scooter is puttering to a halt at the foot of a building adjacent to the Sea Bird Hotel. The hotel is unlit except for a small blue neon sign over the entrance. Villanelle knows which room is Eve's; Konstantin's surveillance people have watched her come and go since the night she and Simon arrived.

The beauty of it is, she had no choice. Konstantin had ordered Janie to make sure that she was never followed to a rendezvous, and to drug the Englishman if necessary. But the little hooker fucked up, and once Simon Mortimer saw Konstantin, he couldn't be allowed to live. That's the way she's going to argue it, anyway. The killing will almost certainly be blamed on the Triads, whose traditional murder weapon is the cleaver. Polastri will get the message loud and clear, but as far as everyone else is concerned -- the press, the police -- Simon Mortimer's just going to be a tourist who found himself in the wrong place, at the wrong time.

Eve's clothes have been hung over a chair, and Villanelle gently runs the back of her hand over the black silk cocktail dress before lifting it to her face. It smells, very faintly, of scent, perspiration and traffic-fumes.

For almost two minutes she crouches there, unmoving. Then she steps soundlessly towards the bed.

Silently, Villanelle climbs up the side of the hotel, the antique pipework and ironwork balconies offering easy hand- and footholds even in the near-darkness, and slips feet-first through the open, third-floor window.

Eve's lying with her mouth slightly open and one arm flung across the pillow. She's wearing a flesh-coloured camisole, and without make-up looks unexpectedly vulnerable. Kneeling beside her, Villanelle listens to the whisper of her breath, and inhales her warm smell. Noting the faint tremor of Eve's mouth, she touches her tongue to her own upper lip which has begun, very faintly, to throb.

Almost as an afterthought, she searches the room. There's a combination-locked briefcase chained to the bed she decides to leave alone. But on the bedside table, there's a pretty, gilt-clasped eternity bracelet, and this Villanelle takes.

"My enemy," she murmurs in Russian, touching Eve's hair. "Moy vrag."

Despite its neglected air Dever is an active station, classified as a top-secret government asset. Among other functions, it acts as a base for E Squadron, a Special Forces unit whose role is to conduct deniable operations in support of the Secret Intelligence Service.

It's five weeks later, and at midday the grey sky over the Dever Research Station promises rain. Set in sixty acres outside the village of Bullington in Hampshire, the former Logistics Corps barracks appears from the outside to comprise little more than a cluster of dilapidated red-brick blocks and prefabricated huts. Chain-link fencing topped with razor wire and signs prohibiting photography lend the place a grimly uninviting aspect.

Identifying himself at the gatehouse, Richard Edwards parks his thirty-year-old S-class Mercedes on an area of cracked tarmac. With the exception of a couple of security personnel who are making an unhurried circuit of the perimeter, the place appears deserted. Making his way past the main administration block, Richard enters a low, windowless building. Descending to the underground firing range, he finds Eve field-stripping a Glock 19 pistol under the watchful eye of Calum Dennis, the station armourer.

"Thank you," she whispers, and with a last look at Eve slips silently out of the window. As she goes she hears the distant siren of an ambulance and the whooping of police cars. But Eve, for now, does not stir.

Eve stares fixedly down the range. "Can I try that last drill again?"

"So how are we doing?" he enquires, when the slide, spring, barrel, frame and magazine have been neatly lined up on the gun-mat.

"Ready when you are," says Eve, putting on her own ear-defenders.

"Sure," says Calum, handing Richard a pair of ear-defenders.

"Getting there," says Calum.

Calum types a series of instructions into a laptop, and as he hits Enter, the range is plunged into darkness. Fifteen seconds pass, during which the only sound is the sigh of the ventilators and a metallic clicking as Eve assembles the Glock. Then a target, a human torso, is briefly illuminated at the far end of the range and she snaps off two shots, the muzzle flash bright in the darkness. Four more static targets appear, and Eve fires paired shots at each. The final target moves from side to side, and she discharges the last five rounds in her magazine in fast succession.

"Well…" Calum says and smiles faintly, lowering a pair of binoculars. "His afternoon's fucked."

Outside, an hour later, Eve's walking Richard back to his car. Rain's falling in a thin mist, darkening her hair.

"It's too late, Richard. That woman killed Simon, and I want her for it."

"You don't have to do any of this," he tells her. "By rights, I should take you off this investigation. Sort you out with an official position in the Service."

"You don't know that. The police report said it was almost certainly a Triad hit, and we know that Janie Chou person he hooked up with had links to organised crime."

He unlocks the Mercedes. Stands there for a moment, head bowed. "Promise me one thing, Eve. That if you find her, you won't go anywhere near her. And I mean anywhere."

"Richard, please, don't treat me like an idiot, the Triads don't chop up tourists. That bitch killed Simon just as surely as she killed Kedrin and the others. I saw his body, she almost beheaded him."

She looks away, expressionless.

"That weapon you insist on carrying. Don't go thinking that a couple of decent groupings on the range gives you any kind of licence to take chances. It doesn't."

He shakes his head. "I should never have got you involved. It was a grave mistake."

"Richard, the reason that I've spent the last ten days here at Dever is that she knows who I am. Killing Simon was a message, addressed to me. She was saying: I can take you, and the people you care about, any fucking time I want…" Eve pats the Glock, now holstered at her side. "I've seen what she can do, and I need to be ready, it's that simple."

"Well, I am involved. And the only way that this thing is ever going to end is if we find her and kill her. So please let me get on with that."

As she walks back towards the range, Richard watches her go. Then he climbs into the Mercedes, switches on the ignition and the windscreen wipers, and begins the drive back to London.