‘So,’ she says with a smile at me. Her manner becomes almost formal as she introduces us. ‘Troy. Yeah, this is Joe. It’s always been just me who can see him. Until now.’ I nod. ‘As you can see Joe doesn’t live in the same reality as us.’ She demonstrates by putting a hand right through my chest. I hear Troy gasp. ‘But he’s real. See – there’s a kind of blue thing about him. Think of the colour blue and look at him.’

Troy walks slowly up to me and reaches out to put his hand on my shoulder. He pulls it back quickly and steps away. He goes as far away as he can get, right to the other side of the tiny room, and presses himself against the wall.

‘Blue,’ he says. ‘Yes. Is this a –’ I can see that he’s desperate for something rational – ‘a hologram?’

‘I’m a ghost,’ I tell him. The words sound quite cool. I don’t think I’ve ever said it quite so baldly before. ‘I’m Joe’s ghost.’

The room is quiet for a long time. In the end Troy says, ‘So you died?’ His voice is shaky.

‘Yes,’ I say. I go to stand next to him and he doesn’t run away. Ariel stands on his other side. Troy is much taller than me. He’s a bit taller than he was at fifteen and much bulkier.

‘I was sure you were alive,’ he says. ‘At first I ignored your message. I thought it was just kids messing around again. But I couldn’t shake it off and in the end I knew I had to come. The frog. The Tory thing. You said things no one else could have known and, even though I tried to ignore it, when it came down to it I knew it was you. As soon as I faced up to that, I caught the first flight to London, and the train here. I was trying to imagine what could possibly have happened. I thought you must have been kidnapped and held hostage somewhere. You hear of it happening, don’t you? About people escaping from a basement or whatever twenty years later. I thought that was why you were contacting me in the way you did.’

I look at Ariel. She stares back at me. We were so sure it was Troy, but he’s not faking this. Our sole suspect doesn’t seem to have done it.

‘Sorry, mate,’ I say, and I sense Ariel trembling. ‘I wish it was that. No, I don’t. I don’t know what I wish.’

‘Tell me what happened.’

We sit on the bench, the three of us in a row with Troy in the middle, and Ariel and I tell him everything. He mainly listens in silence until he enters the story, when Ariel describes sitting in a cafe by a London canal with Lucas.