Have you ever been compelled to take a step that you know is a mistake but you simply can’t stop?

The return home from the Tate Modern is a blur. I walk through the streets of London blindly, telling myself over and over again that I did it for Luke. I try to remember him, but his image eludes me. All I see is Jake, shirtless on a horse, Jake looking at me. Jake standing blood-splattered in Melanie’s apartment. Jake with tears in his eyes. Jake holding me. Jake kissing me. Jake smiling. Jake laughing. Jake. Jake. Jake.

I stop walking and hold my head. It feels as if it is about to burst.

‘Are you all right?’ someone asks.

I look up. A man is looking at me. He seems concerned. ‘Yes,’ I say automatically. Nothing could be further from the truth.

‘OK,’ he says, and moves on.

Robin’s words flash into my mind.

At the end of the operation you will ditch all the physical trappings of your undercover alter ego, the hair, the clothes, the people you have befriended, and return to your own normal world.

A small, hesitant voice in my head asks, what about the people you fall in love with? I drum it out with the militant message they have brainwashed me with. First and foremost you are a police officer.

I have done the right thing.

I walk until my legs start to ache, then I stop and hail the first taxi I see. Inside it, I sit with my face turned toward the window, seeing nothing. The taxi drops me outside the house. I watch it drive away and stand at the bottom of the short flight of steps for an age. My legs are like lead. Eventually, my heart weeping, I climb the steps.

I open the front door and I know straight away: he is home. I walk down the corridor and open the living room door.

Seeing him is like jumping into an icy river. The guilt. God, the guilt. I know: I’m in too deep. I have broken the most important rule—I didn’t keep what I am doing and who I am separate. I have allowed myself to get psychologically mixed up.

He is sitting on the white leather sofa, but he must have been pacing the floor until he heard me at the front door, because there is that look of restlessness about him. A glass of Scotch sits on the table. He looks pale under his tan and his green eyes burn feverishly bright in his face.

I smile as I shatter inside. The heaviest tears never reach the eyes.

He doesn’t smile back. He seems very still. His eyes hold onto me so hard it almost hurts.

‘Hi,’ I say.

‘Where have you been?’ I see that his hands are clenched hard and he seems to be controlling himself.

‘I was shopping.’

His chest heaves and his eyes flick to the bag in my hand. ‘Why did you not answer your phone?’

‘I had it on silent.’

He nods gently, but seems somehow inconsolable. I feel the vibrations of his despondency in my blood as if it were my own.

‘I’m sorry, I didn’t think you would worry,’ I murmur.

He takes a deep breath. Again I see him making a Herculean effort to control himself. ‘You were attacked less than a week ago, Lily.’

‘I’m really sorry,’ I say again.

‘You look tired,’ he observes.

‘I am.’ I try to smile at him.

‘Come here.’

I go to him and climb into his lap. His hands come around me, the palms hot. I nuzzle him like a cat, my hand stroking his thick hair, straightening it. It is ruffled. He has been running his hands through it. He takes my shoes off and lets them drop with a thud on the floor. I sigh with pleasure when his big hands start massaging my foot.

‘I didn’t know where you were. If you had simply run away. I know so little about you.’ His voice is a deep, honeyed rumble. It has a song in it. I could listen to it all my life. But I won’t. I was fooling myself before.

‘I didn’t run away. I’m here.’

The hardness between his legs pushes into my hip. I look up into his eyes. There is only one word for what is in them: hunger. I have never seen such extreme desire, such ravenous craving. The air trembles with it. A voice inside my head cries, ‘What have you done? What have you done?’ I ignore it. My body loses its tiredness and responds to that yearning. My lips part, my nipples swell and pebble tightly, my sex opens like a night flower.

‘Would it be really horrible if we had sex right now?’ he murmurs.

‘Yes, that would be utterly, utterly horrible.’

He carries me to the bedroom and kicks the door open. The large chandelier is not lit. Instead only the narrow bronze lamps over the paintings on the walls are on, creating their own individual pools of yellow light, making the paint look thick and oily. I glance at the bed and my mouth opens with astonishment. I turn back to look at his face. ‘What the—?’

‘Indulge me,’ he says languidly and throws me on the bed covered thickly with money.

‘Oh,’ I gasp.

‘Get naked,’ he orders.

Giggling, I pull my top over my head and, lifting the upper half of my body slightly, unclasp my bra and pull it off. I raise my hips off the bed and shimmy out of my skirt. There are only my panties left.

‘Help me,’ I say.

He reaches down and, sliding his hands along my bare thighs, pulls them down my legs and flings them over his shoulder.

Hungrily he looks down at me lying naked on a bed of money. I gaze up at him, and slowly biting my lower lip, grab two handfuls of money, and throw them up into the air. They fall over and around me.

‘Hello,’ I say, covered in his dirty money.

He nods slowly, formally. As if he approves of my actions. We continue to stare at each other. I could have stayed there looking up at him forever. I actually feel faint with longing. He is so beautiful, I want to reach out and touch his skin to see if he is real.

‘Do it again.’

I lift handfuls of money and pour them onto my body. One note lands on my mouth. I blow it away. Here I am, an undercover cop, bathed in money, about to fuck a criminal, and not wanting to be anywhere else in the world.

He gets down on his haunches and cupping my buttocks in his large hands, lifts my hips bodily and, bringing my open sex toward his face, deeply sniffs in my female scent. I have been walking all day and I imagine the smell to be scandalously strong and musky. But I am not embarrassed. I know he likes dirty sex. This is the man who thinks warm raw sea urchin tastes good.

He lets his tongue swirl between the pink folds. The velvet brush is succulent, bringing with it whispers of sensations. Deep within I begin to tremble indescribably. My body instinctively arches, and my hips grind into his mouth, feeling his teeth, and begging for more and more. He slips his fingers into me. I grab his head and force it against me. With his fingers impaled inside me, his tongue works my clit.

‘Get up on your elbows and let me look at you.’

I obey his demand and look into his eyes. They look stunning. He gazes into my glazed ones. Suddenly, I can’t hold his gaze. I am the dirt that has betrayed him. I close my eyes.

‘Open your eyes and look at what I am doing to you.’

I open my eyes and, unable to meet his eyes, watch his mouth fasten down on my sex and suck it like a hungry babe at its mother’s breast. My body feels no guilt. It pushes me on until I break apart with a stifled cry inside his mouth, his fingers deep inside, his eyes trained on me, my head thrown so far back it touches the wings of my shoulder blades.

I lift my head slowly.

He is watching me, his lips shining with my juices. ‘I like watching you lose control.’

I flop back down on the bed, roll over, and getting on my hands and knees, money sticking to my damp skin, offer my throbbing, eager sex up to him.

‘Lay your face on the bed,’ he growls. The sound wells up from deep inside him.

I hear the sound of his trousers hitting the floor as I lie on my cheek. The scent of money rises into my nostrils: soiled ink, slightly disagreeable. He grabs my hips, and, with a snarl of hungry desire, plunges into me. His cock feels more swollen than usual, voluptuous. I marvel at the sensation even as my muscles ripple around him to accommodate the intrusion. Coated in hot, slick juices he pushes in harder. I tilt my hips so he slides in deeper.

‘Who does this hole between your legs belong to, Lily?’

‘You,’ I gasp, as another thrust makes more notes detach from my body and rain down on the bed.

Another thrust. ‘Say it again.’

‘You,’ I pant.

‘And who do you belong to?’

‘You. I belong to you.’

And with that he explodes inside me, wild, hot cum shooting into me.

I hear him breathing hard. With me still speared to his body, he leans forward, his body barely brushing my back. He kisses me on the base of my neck where there is a little nerve that makes me shiver, and whispers in my ear, his breath hot and moist, ‘You can keep all the money you can hold in your hands.’

Baffled, my spine prickling, I turn my head back to look at him. Is he…?

But his face is innocent.

He moves back and pulls out of me. My body immediately misses him. I watch his eyes latch onto the blood-engorged, reddened flesh between my legs, his milky seed seeping out.

I can read his mind. If I stay in that position one moment longer he will slide his fingers into me. I crawl forward and sit cross-legged on the money. There is a note stuck to my calf. I peel it off, thinking of Melanie, thinking of her saying, ‘I take their money and spend it and that is my revenge.’

Dust motes are swirling magical specks in the last rays of the evening’s sun pouring in through the windows.

I let my gaze travel over the notes. They are mostly tens and twenties. There must be at least fifty thousand pounds I am sitting on. I could ask where the money has come from, but I remember Robin saying, Let some chances to ask for information go by. Don’t even appear curious. Lull him into a place of complete trust before you sink the hooks in. So he wants to play the games low-level gangsters employ to show off to their women? When again our eyes clash my face is calm, my thoughts hidden.

‘Do I have a time limit?’ I ask.

‘Nope.’

‘OK.’ I start gathering the money, carefully, in bricks. Afterwards, without looking at him, but knowing he is watching me, I slide the bricks together. Six bricks. I double them so their height will be slightly higher than my palm and fingers spread to their fullest. I push them together and notice a note lying on the floor. I look up at Jake, standing with his arms crossed over his chest.

I arch an eyebrow. ‘Do you mind?’

Wordlessly he bends, picks it up, and holds it out to me. I take it and, putting it on top of my pile of bricks, lift them all by pressing them together on either side of the tower with my spread palms. The whole thing comes up in between my palms.

I look up at him, fifty thousand pounds richer.

He grabs my hand—the bricks fall down on the bed in a heap—and pulls my naked body to his. ‘Do you know what I am thinking?’ he mutters.

My heart somersaults. I take his lower lip between my teeth and pull it experimentally as far away from his face as I can while my hands start undoing the top button of his shirt. He drags his lips in a trail of fire along my throat and my chin and catches my mouth with his. His tongue delves in, seeking mine, like a grounded child whose friend has come to knock on the door to ask if he can come out to play.

‘Someone should bottle you,’ he says softly, much, much later.