He nods, still unhappy, and then revs the engine and I watch as his car disappears into the falling dusk, the red tail-lights illuminating the falling snow.

Jesus, this drive is long. I had forgotten how long. I remember the run, when I met Clare halfway up, my legs tired and aching and my skin cold.

That was nothing to this. What has happened to my muscles in hospital? I’m not even halfway up and my legs are trembling with those muscle shakes that come after you’ve pushed yourself too hard and too fast. My feet in the hard plastic flip-flops are bleeding, but they’re so numb I can’t feel any pain, I only know what has happened from the smears of red that mingle with the flecks of snow.

The mud, at least, has frozen, so I’m not fighting against the cloying lumps sticking to my feet. But when I stumble into a particularly deep rut there’s a crack, and my foot goes through the thin crust of ice into the freezing pool of muddy water beneath.

I gasp and make a kind of squeaking whimper as I pull my foot painfully out through the sharp ice. It is a thin, pathetic sound, like a mouse being caught by an owl.

I am so cold. I am so very, very cold.

Have I been very stupid?

But I have to carry on. I’m halfway. There’s no sense in going back – even if I could flag down someone on the road, where would I go? Back to the hospital and the waiting cuffs of Lamarr? I’ve run away, absconded. I have to see this through. There is no way back.

I force my feet, one in front of the other, my arms wrapped around myself for warmth, thanking God and Nina for the blue cardigan which is the only thing keeping me from hypothermia. The wind blows again, a low moaning howl through the trees, and I hear the snow shake and patter to the ground.

One more step.

And one more after that.

I cannot tell how close I am – with the house empty, there’s no glowing lights to guide me. I have no sense of how long I’ve been walking in this bitter cold. Only that I have to keep going – because if I don’t I will die.

One more step.

There are pictures in my head as I get closer. Flo, her face twisted with fear, the gun across her chest. Nina’s horrified expression, her blood-stained hands as she tried to staunch the flow.

James. James lying in a pool of his own blood, dying.

I know now what he was trying to say, when he said te … Leo?

It wasn’t ‘tell’ it was ‘text’. He was asking me why I’d brought him here. And why I’d let him die like this.

He came for me. He came because I asked him.

Did I ask him?

I’m no longer sure. Oh my God, I’m cold.

It’s hard to keep things straight in my head.

I remember the texts Lamarr showed me on that printed paper and I’m no longer sure if I’m remembering them from when she showed me, or before that.

Did I ask James to come?

I didn’t know that Clare was marrying James until she told me in the car. I didn’t know. So why would I have texted him?

I must cling to that – I must cling to what I’m sure of.

It must have been Flo. She was the only person who could have controlled all this – who chose the guests, who picked the house, who knew about the gun.

She was in the house when the texts were sent.

She knew I’d gone for a run.

I think again of her strange intensity, of her huge, explosive, terrifying love for Clare. Is it possible that she thought she might lose Clare to James? That she couldn’t bear for him to come between them? And what better person to pin the blame on than me, James’s ex-girlfriend, Clare’s best friend.

And then … then she realised what she had done. That she’d destroyed her friend as well as her rival. That she had ruined Clare’s life.

And she couldn’t take it any more.

Oh my God I’m so cold. And so tired. There’s a fallen tree by the side of the lane. I could sit on it, just for a minute, just to stop the shaking in my legs.

Step by laborious step I make my way to it, and sink down onto its rough, moss-covered side. I huddle my body down to my knees, breathing into my legs, desperately trying to conserve some warmth.

I shut my eyes.

I wish I could sleep.

No.

The voice comes from somewhere outside me. I know it’s not real, and yet I hear it in my head.

No.

I want to sleep.

No.

If I sleep, I will die. I know that. But I don’t care any more. I am so tired.

No.

I want to sleep.

But something won’t let me. Something inside me won’t let me rest.

It’s not a desire to live – I don’t care about that any more. James is dead. Clare is hurt. Flo is dying. There is only one thing left – and that is the truth.

I will not die. I will not die because someone has to do this – has to get to the truth of what happened.

I get up. My knees are shaking so much that I can hardly stand, but I do, steadying myself with a hand on the fallen tree.

I take a step.

And another.

I will keep going.

I will keep going.

30

I DON’T KNOW how long it takes me. Dark has fallen The hours seem to drift together, blurring into the snow that is speckling the frozen mud. I am tired – so tired that I can’t think, and my eyes water as I walk into the wind that has begun to blow.

My face is quite numb, and my eyes are wet and blurred when, at last, I look up, and there it is: the Glass House.

It’s no longer the great golden beacon I saw that first night – instead it’s dark and silent, blending into the trees, almost invisible. A half moon has risen, and it reflects off the bedroom window at the front, the bedroom that Tom slept in. There’s a frost halo around it, and I know the night is only going to get colder.

The darkness is not the only difference. There’s police tape across the door, and the broken window at the top of the stairs has been boarded over with a kind of metal grille, the sort you see on vacant houses in rough areas.

I walk the last few painful yards across the gravel and stand, shivering and staring at the blank glass wall in front of me. Now I’m here, I’m not sure I can do this, go inside, revisit where James died. But I have to. Not just because of James, not just because it’s the only way I will ever find out the truth about what happened. But because if I don’t get inside, into shelter, I will die of exposure.

The front door is locked, and there are no windows I can force. For a moment I pick up a rock and consider the huge glass wall of the living room. I can see inside, to the cold, dead wood burner and the flat blackness of the TV screen. I imagine heaving the rock at the giant pane – but I don’t. It’s not just the huge noise and destruction, but I don’t think it would break – the pane is double, maybe even triple glazed. It took a shotgun blast to break the one in the hall; I’m pretty sure my puny rock would just bounce off this one.

I drop the rock, and make my way slowly, painfully around to the back of the house. My feet are totally numb, and I stumble more than once, seeing the blood coming up between my toes as I do. I push away the thought of how I will get away from here – I can’t walk, that’s for sure. But I have a horrible feeling it will be in a police car. Or worse.

The back of the house looks equally unpromising. I try the long, sliding French door to the rear of the living room, prising my nails around the flat glass panel and trying to pull it sideways, hoping, desperately, that the catch is not locked. But it stays firm, and all I manage to do is break my nails. I look up at the sheer side of the house. Could I climb up to the balcony where Nina smoked?

For a minute I consider it – there’s a zinc drain pipe. But then reality bites. I’m kidding myself. There’s no way I could climb that slippery glass wall, even with climbing shoes and a harness, let alone in flip-flops and with numb fingers. I was always the first person to fail the climbing ropes at school, hanging there pathetically, my skinny arms stretched above my head, before I dropped like a stone into a crumpled heap on the rubber mat, while other girls swarmed to the top and smacked the wooden bar overhead with the flat of their palm.

There’s no rubber mat here. And the zinc pipe is slippier and more treacherous than a knotted gym rope. If I fell, it’d be all over – I’d be lucky to get away with a broken ankle.