Waterhouse lingers. ‘You came to us, remember? Or does your memory wipe out things that have happened as well as inventing things that haven’t?’

He’s gone. They’re both gone. Aidan slams the door, leans his head against it. Once he’s breathing steadily again, he says, ‘You said you went to the police. You didn’t tell me you went to Charlotte Zailer.’

I haven’t got the energy to pretend it was a coincidence that she turned up. Let him think what he wants.

‘She’s not your friend, Ruth. She might mean something to you, but you’re nothing to her.’

‘Where’s the picture? Abberton—what have you done with it? Tell me what’s going on.’

‘Do you believe what Waterhouse said? That my memory’s inventing things that haven’t happened?’ He starts to come towards me. ‘If it hasn’t happened, it’s not a memory. Do you think it’s possible to see the future?’

‘No. What do you mean?’

‘A clear image—like a photo, or a film—of something that hasn’t happened yet but is going to happen.’

‘No! Stop it! You’re scaring me.’

‘Me strangling that bitch Trelease—putting my hands round her throat and squeezing . . .’

‘Don’t.’ I back away from him. He looks determined and, at the same time, terribly afraid. Like a man walking into a fire.

‘They say she’s alive. You say she’s alive. Maybe you’re all right. If you’re right, then what I’m seeing in my head can’t be the past. What if I haven’t killed her, but I’m going to?’

‘Aidan, don’t do this,’ I beg, putting my arms round him. He’s rigid, like stone. ‘What you’re saying’s not possible.’

‘Abberton,’ he mutters. ‘It’s part of a series. She hasn’t done them all yet—maybe only that one, the first. But she’ll do more. I can tell you how many there are going to be: nine. I can tell you what their names will be.’ He pushes me out of the way, pulls the lid off a blue marker pen and starts to write on the side of a cardboard poster tube. He reads aloud as he writes, like someone in a trance. ‘Abberton, Blandford, Darville, Elstow, Goundry, Heathcote, Margerison, Rodwell, Winduss.’

I stare at him, wondering who he is, who he’s turning into. He’s sane. When I told Charlie Zailer that, I believed it. ‘Aidan, you’re making no sense,’ I say shakily.

He grips my arm. ‘Go back to Megson Crescent,’ he whispers, his face close to mine. ‘If it’s the future, it can change. It has to change. Tell her not to do the other paintings—make her stop. Tell her to get out of Spilling and go somewhere I won’t find her . . .’