This frozen state can last for hours, and then, like dawn breaking, she'll wake to my presence. At these times I've learned to wait and see which way the cat jumps, because she's so unpredictable. Sometimes she's pensive, just wanting to be held, sometimes she's as sullen and spiteful as a child. When she wants sex, she reaches for me. After four days and nights at sea, this has become a raw, feral business. We need the water that we have for drinking, washing is impossible, and our bodies are rank. Not that either of us cares. Villanelle knows what she wants and goes straight for it, and with the last of my inhibitions dispelled by the darkness and the desperate uncertainty of our situation, I'm soon giving as good as I get. Villanelle likes this. She's much stronger than me, and could easily throw me off when I pin her down and roll on top of her, but she lets it happen, and lies there as I stroke her breast, and my tongue and my teeth probe for the scar tissue on her lip. And then she grabs my hand and pulls it downwards, cramming my fingers inside her, and grinds against the heel of my palm until she's gasping, and sometimes laughing, and I can feel the muscles of her thighs twitching and shuddering.

She withdraws. She locks herself into the secret citadel of her mind. I'm sitting there next to her, her leg warm against mine, our breath mingling, but she could be a thousand miles away, so arctic is her solitude. Sometimes it happens when we lie down to sleep and she burrows into me for warmth. Part of her is just not there. I long to tell her that she's not alone, but the truth is that she's utterly alone.

I'm beginning to learn Villanelle's ways.

"It wasn't interesting. Ever. I hoped to find emails from a lover or whatever. But it was just orders for bin liners and moth traps and awful, ugly clothes."

"You did tell me that, yes."

"That's right. Billy and Lance. Did you think about having sex with them?"

"A rat?"

"Exactly."

"Billy and Lance."

"Sweetie, take my word for it. You're the first."

This is a conversation we've had before. "You know I am," I tell her.

"I was mostly trying to catch you, if you remember. An entire MI6 team was trying to catch you."

"Mmm."

"That's what you were doing in that shitty office all day? Thinking of having sex with me?"

"You've never been with another woman?" she says. "I'm really your first?"

"I don't know."

"I thought about it a lot. What it would be like with you. What we might do."

"Literally never. Billy was a computer wonk who lived with his mum, and Lance was a bit like a rat. A super-cunning, well-trained rat, but still, you know…"

She considers this for a moment. "You know that when I was bored, in Paris, I used to hack your computer."

"You never got close, pupsik. What were they called, those losers you worked with?"

Her breathing slows. "I could have killed you, Eve. So easily. But I didn't. I saved your life, and I risked my own, which to be very honest with you was a fucking stupid thing to do. But because I care for you, I got you away from London, and the Twelve, and that asshole husband you never loved, and I'm taking you to my country. So what do you do? You laugh at me because I don't know what fucking Rinse-Aid is."

"You kill people for a living and you're criticizing my knitwear?"

I kiss her nose. "It doesn't matter."

"No. Why?"

"Don't call me 'Sweetie.' I'm not your sweetie and you're not mine. You know my girlfriend is in a Moscow prison because of you?"

"Life doesn't have to be so sad. You don't have to buy acrylic sweaters, for example. Even moths think they're disgusting."

"I'm not. Really I'm not."

"Sweetie, have you never used a dishwasher?"

"It's not the same thing, Eve. Clothes matter. And what's Rinse-Aid? Is it for your hair? Some kind of charitable organization?"

"And now you're laughing at me. Again."

"Sweetie, I'm --"

"Sorry. That's called life."

"She is."

"If you mean Larissa Farmanyants, she's hardly there because of me. She tried to shoot me in a crowded Metro station, missed, killed a harmless old man and got herself arrested."

"I'm thrilled. Have you finished?"

"And now she's locked up in Butyrka. Well, you know what? I wish you were there and Lara was here. She used to lick my pussy for hours on end. She had the most powerful jaws of any woman I ever met, like a pit bull."

"Being such a spoiled, manipulative little bitch."

"She sounds adorable."

"I'll be any kind of bitch I want. I created you, Polastri. Show some fucking gratitude."

"Finished what?"

She's such a jagged cluster of contradictions. I had no idea that anyone could be so ferociously self-sufficient, and at the same time so emotionally unstable. One moment she's flirtatious and tender, covering my face with kisses, the next she's spitting the most wounding things at me that she can think of. I know her cruelty is just a front, a way of protecting her fragile sense of self, but it pierces me like a knife every time. Because right now, if I don't have her I don't have anything. And she knows it.

We talk. In fits and starts to begin with, but soon for hours on end. Talking distracts me from the painful stomach contractions I've started experiencing. When they started, like a snake coiling tighter and tighter in my guts, I was afraid I had gastroenteritis or a knotted intestine. I told Villanelle and she laughed, prodded my stomach with a hard finger, and told me I was hungry. "I had this often when I was a child. It will be bad for a day or two then it will go."

Why is she doing it? The staging of my death and our escape from London was so bold, so meticulously executed. Why is Villanelle going to so much trouble on my behalf? Does she really care for me, or am I just a fixation, an itch that she has to scratch? And what about me? What do I feel, beyond the fact that I want her, desperately, and live for the moments when we reach for each other in the darkness?

Perhaps I shouldn't be surprised at Villanelle's behavior, because although it's crazy to get upset about Rinse-Aid, it makes me realize just how utterly solitary her existence has been. She's never used a dishwasher because she's never needed one: she's always lived and eaten alone. In choosing to save my life, and in doing so risking her own, she went against her own nature.

She always starts by boasting. She loves to describe the revenge that she's visited on those who have underestimated her (a long list), and the ease with which she's outwitted those trying to apprehend her.

"And then what?"

"I'm kidding. You'll be fine. I knew a fashion model in Paris whose daily diet was a single Ladurée macaroon."

"Wow. What flavor?"

"Pistache."

"Too late."

"Oh my God. I'd sell my soul for a pistachio macaroon right now."

"What about?"

"Your soul's mine now. It's not for sale. You have to starve."

"What do you mean?"

"Shit. OK, just keep talking."

"Tell me about Paris."

"Then your internal organs start to dissolve."

"I loved it. I was une femme mystérieuse. No one knew who I was, but I'd see people staring at me, and I'd think, fuck, if you only knew. But of course they didn't know. And that felt so good. There was this one guy, very rich…"

"Great."

Her tendency to fictionalize her life makes it hard to establish a definitive story, but I already know the basic facts, and gradually I fit the pieces together. She was born Oxana Borisovna Vorontsova in Perm, a second-tier industrial city near the Urals. Her mother died of cancer when she was young, her father was a soldier, often absent. Diagnosed with an antisocial personality disorder, Oxana endured a lonely and friendless childhood. She excelled at her studies but was often in trouble for violent and disruptive behavior. While at secondary school she formed a close attachment to her French teacher, a woman named Anna Leonova. One night, after school, Anna was sexually assaulted at a bus stop. A local youth was suspected of carrying out the attack, and shortly afterward he was discovered incoherent and suffering from massive blood loss. "I castrated him," Villanelle tells me with a touch of smugness. "I pretended I was going to give him a blow job, then cut off his balls with a knife. No one guessed it was me."

In fact, the local police had a pretty good idea who was responsible. They already had a juvenile file on Oxana Vorontsova, but abandoned the investigation for lack of evidence. They would be more tenacious when Oxana, by now at university, was arrested for murder. The victims were three local gangsters who, she claimed, had killed her father. This accords with what I was told by Vadim Tikhomirov of the FSB, although Villanelle's version of events differs substantially from the official report. According to her, her father was working undercover for the security services, and had infiltrated the gang. According to the police, he was a low-grade enforcer for the gang and had been caught stealing from his bosses.

While she awaited trial, Oxana's release from prison was engineered by a man named Konstantin. She never knew his full name, but it's probable that this was Konstantin Orlov, a former intelligence officer of considerable distinction and reputation. Orlov had for some years run the FSB's Directorate S, a secretive bureau whose operational remit included the elimination of foreign enemies of the Russian state. By the time that Oxana encountered Orlov, it appears that he was performing a similar service for an organization called the Twelve. "He knew everything about me, right back to my childhood," Villanelle remembers with pride. "He told me that I had been born to change history."

What this meant in practical terms was that she became a paid assassin for the Twelve. Orlov supervised her training, and later became her handler, installing her in the apartment in Paris, and at intervals dispatching her on kill missions.

Villanelle loved her new life. The airy apartment overlooking the Bois de Boulogne, the money, the beautiful clothes. She even made a friend, a wealthy young woman named Anne-Laure, with whom she shared lunches at fashionable restaurants, shopping trips and occasional ménages à trois. I think that what she loved even more than this gilded existence, though, was the secret thrill of knowing that she wasn't the person the world thought she was. When she looked in the mirror, she saw not a chic young socialite, but a dark angel, a bringer of death. She was addicted as much to the secrecy as to the killing itself.

She still is. She doesn't tell me her plans for when we get to Russia because withholding this knowledge gives her power over me. Whether I can persuade her to relax her grip, I don't know. I hope so, because if we can't trust each other we're not going to make it.

"I didn't. You're just making that up."

"What?"

"Girlfriend. Girlfriend, girlfriend, girlfriend. Enough?"

"You kicked me literally all night."

"Say that again."

"You farted all night."

"Say what again?"

"A psychologist, too. This is fascinating."

"Fuck's sake, Villanelle."

"Right, you're a doctor now?"

"Past tense of shit is shat? You're shitting me."

"Funny girl. Yes, it's irregular."

"Like you, pupsik. And you know why you haven't shat for a week? Because you're repressed."

"Shat."

"You're embarrassed. So you hold it in."

"I do no such fucking thing."

"You should kill a few people. Get it out of your system. Then you mightn't be so uptight about shitting in front of your girlfriend."

"Eve, since we left London you haven't shitted once."

"Girlfriend."

I'm not the person I was. The events of the last week have shown me the shadow self I've always denied, and forced me to hear the backbeat I've always pretended wasn't there. All my certainties have evaporated. Villanelle has deleted them.

"I'm not. It's because you don't shit."

"You're so whipped."

"No. Never stop."

"I know. Come here."

Somehow, I drift off. When I wake an unquantifiable time later the wind has dropped, my stomach cramps have gone, and Villanelle's sleeping body is warm against my back. I lie there unmoving, her arm heavy on mine, her breath whistling across my ear. Careful not to wake her, I maneuver myself into a position where I can see my watch. It's gone 6 a. m., Baltic time. Outside the day is dawning, cold and dangerous.

The last night in the container is the worst. The wind screams across our bow, pounding against the container stacks so that they creak and groan. In the darkness, my hunger pangs and the vessel's pitch and roll join forces to nauseating effect. I draw my knees up against my chest and lie open-eyed as acid rises into my throat. Then I'm on my hands and knees, retching uncontrollably, but there's nothing in my stomach to come up. The wind continues its assault for hours, until my body is wrung out and my throat raw from dry heaving.

Throughout it all, Villanelle says not one word, makes not a single sympathetic gesture. A touch would do it, but none is forthcoming. I don't know if she's asleep or awake, angry or indifferent. She's just not there. I feel so utterly abandoned that I half-expect to find myself alone when the morning comes, if it ever comes.

"You were awake? Why didn't you say anything? I thought I was going to die."

"What should I have said?"

Finally, Villanelle stirs, yawns, stretches like a cat, and buries her face in my hair. "Are you OK? You sounded awful last night."

"You weren't going to die, pupsik, you were seasick. There was nothing I could say to make you feel better, so I went to sleep."

"Couldn't you have said something?"

"I felt alone."

"I was right here."

"Fuck, I don't know, Villanelle. Just something to tell me that you knew how I was feeling?"

"But I didn't know how you were feeling." She gets to her feet and stumbles across the clothing bales to the safety hatch. A minute later the interior of the container is illuminated with a thin morning light. Pulling down her leggings and pants, Villanelle squats over the bucket. In her thick sweater she looks shapeless and bedraggled, her hair standing out from her head in spikes. I follow her to the bucket, pee in my turn, then carry it over to the hatch and pour it out. The urine freezes immediately, thickening the cascade of yellowish ice streaking the container's exterior.

"You won't lose me, pupsik. But you have to trust me."

"I do. And I don't want to lose you."

Bracing myself against the sub-zero blast of the wind, I search the horizon. Slicing between sea and sky is a faint, gray knife blade. I'm not sure if it's a trick of the light, so I find my glasses in my bike-jacket pocket and look again. It's land. Russia. I stare out of the hatch, trying to focus my thoughts, and then Villanelle is beside me, her cold cheek pressed to mine.

"Yes."

I turn to her, and we hold each other, my fingers in her greasy hair, hers in mine. "It's been a good honeymoon, hasn't it?" she says.

"Are you scared?"

Sniffing, she wipes her nose with her sleeve. "When we get there, you do exactly what I say, OK?"

"No, but I'm not normal. You know that."

"I'm scared. I'm really fucking terrified."

"OK." I watch as the silhouette of St. Petersburg slowly hardens. "Villanelle?"

She slips a hand under my sweater and over my heart. "It's not a problem. Being scared when you're in danger is normal."

I stiffen. "I've never called you that. Ever."

"You don't mind me being a psychopath?"

"It's been perfect."

"Not to my face." She bites the lobe of my ear. "But it's what I am. We both know that."

"Listen, Eve. I know you want me to, you know, try to feel the things that you feel…"

"I'll try to be more normal, OK, but if we're going to survive, you're going to have to be a bit more like me. A bit more…"

I stare out through the safety hatch. Other container vessels are visible now, converging on the distant port.

"More Villanelle?"

Whether it's from hunger, lack of sleep, or just the freezing wind, tears spring to my eyes. "Sweetie, it's OK, really it is. I… I'm happy with how you are."

She brushes my neck with her chapped lips. "A bit more Oxana."