The hall light blazes and a minute later the door opens to reveal Seb in a washed-out blue dressing gown, squinting against the light.

‘Xander, where have you been?’ he says.

‘I’m sorry,’ I say. ‘I had nowhere else I could – and I really need—’

He holds up his hand to wave away the explanation. ‘No need. Come in. It’s going to freeze tonight.’

I expect him to go straight back upstairs but instead he wanders into the living room, turning to me as he walks in.

‘Whisky?’ he asks, clicking on a lamp to give the room a warm glow.

‘Sure,’ I say, and follow him in.

‘The police called for you earlier,’ he says with concern. ‘Look. I don’t want to pry, but what’s going on with you?’

I sit in one of the plush cream chairs. I owe him an explanation but I can’t muster the effort that the explanation will involve. ‘It’s nothing,’ I say.

He looks at me, disappointed, before turning to the whisky and pouring an inch into crystal glasses.

‘I’ve reported a crime but the police aren’t taking me seriously.’

‘Anything I can do?’ he says, handing me a glass.

I shake my head and as I take the glass, I’m drawn again to the picture on the mantel. I stare at it as Seb stretches himself on the sofa, bare heels in the soft carpet. Grace peers out shyly from the image. Something about her expression, soft and smiling, is heartbreaking.

‘Do you remember that?’ Seb says, watching me. ‘Nina had just got herself one of those SLR cameras. You know the ones with the fancy zoom lenses.’

I shake my head. There is the frayed edge of a memory there but not much more.

‘Yes, you do,’ he says, taking the frame into his hands. ‘She wanted each one of us to take a picture of the other three. That’s the one you took.’

I get up and sit next to him on the sofa to look more closely at it. ‘I remember bits,’ I say. ‘But I have trouble clinging on to much from those days. It’s being outside, the exposure. Messes with the wiring, I think.’

Seb nods as if he understands but I’m not sure whether he does exactly.

‘I still see Nina from time to time,’ he says then.

‘Oh. How is she?’ I say. And then I wonder about Grace. Has he seen much of her? I want to ask but that thread, wherever it leads, is too sharp. Painful.

‘The same. You know what she was like, too clever for her own good.’

I smile. There is Nina at eighteen, out-talking and out-arguing a professor during a tutorial. ‘Too smart for you at any rate,’ I say. And then I realise I don’t know how long they’ve been apart. Or together.