The internet had barely existed in those days, but there were enough old articles uploaded to make it clear what had happened, and he was name-checked in more recent pieces over the years, almost always on a list of unsolved disappearances.

I passed him my phone, and he tried to take it, but either his hand went right through it, or it went right through his hand. He pulled his fingers back and I held the phone up in front of him so he could read the screen, and scrolled when he nodded.

Joe Simpson, fifteen, had gone missing the night before his school trip to France. Today, for him. His friend Troy had said goodbye to him outside school, as Joe was going into town and Troy was going home to pack. That was twenty years and two days ago, and Joe had never been seen again, except for an appearance on CCTV at the shopping mall. The general feeling was that he’d ‘done something stupid’. That was code for killing yourself. Yet he was right in front of me and he had no idea what had happened, no intentions in that direction at all.

Also, they hadn’t found his body.

I was looking at a boy who had vanished from his own life twenty years ago, yet who, somehow, was here with me. A boy who had said goodbye to his family one day and never gone home. A boy who was missing, and very much presumed dead.

I might have been the only person who had seen him since 1999. My thoughts pinballed around. Should I tell the police? His parents? Who could I talk to? What could I do?

I reached out again, just to check. My hand went through him.

I looked into Joe’s face and saw my own horror and confusion a thousand times over. It was weird for me, but this was everything for him. He was shaking, trembling all over as if there was something trying to get out from inside his skin. I couldn’t comfort him because I couldn’t touch him. Blue light filled the room.

‘Today,’ he whispered. ‘Now. That happened now. I know you saw me yesterday too, but I don’t remember. Though it kind of echoes, when I think about it.’

‘We’ll work it out,’ I said. ‘I mean, I’ll do everything I can to help. We’ll find out what’s going on. Do you want me to see if I can find –’