As I sit here I try to make sense of what I’ve just read. Grace and Isobel had been friends. Very close friends. Yet when I’d mentioned Grace to Isobel at the party earlier she said she barely knew her. Still, there is no mistaking who wrote that account. The adult Grace’s voice was unchanged from the teenager whose words I’ve just read. The intensity, the digression of thought – jumping from present to past and back again via a circuitous route, taking in all sorts of byways and vistas – but at the heart of it an integrity, a sense of right and wrong, good and evil, light and darkness. That was Grace all over and it was that innate goodness that drew me to her, that made me open up to her, tell her things I hadn’t ever told another soul.

And yet here she was at the age of thirteen planning an act of violence so extreme it called for the inclusion of a gun. Her words were like little explosions scattered across the page. Her hatred of Steve was palpable. But had she killed her father? I shiver as I imagine the deathly silence that must have descended on the woods that night, the fear Grace must have felt.

It’s the same fear I am feeling now.

‘Joe,’ I whisper as I lie down on the floor, curling my knees up to my chest. Please let him be all right. Please let Isobel get my message and come and let me out of here so I can find my baby. Please.

I take my phone out of my pocket and shine the torch at it, hoping, crazily, that the phone has somehow managed to charge itself in the last few minutes. But the screen is still dark.

My eyes are sore and heavy from crying and I tell myself that I’ll just close them for a few moments, but soon I’m falling into a heavy darkness that wraps itself round me like a blanket.

I hear a scream.

‘Joe,’ I call out. ‘Joe. It’s okay, Mummy’s coming. I’m going to be right with you. Any moment now I’ll see you and I’m never going away again. I promise.’

‘Mummy!’

His voice is agitated. He’s somewhere out there looking for me and though I can hear him I can’t see him. I try to stand up but something is holding me back, a weight pressing down on my legs.

‘Mummy!’

His voice is getting closer, so close I can almost smell his milky scent. My beautiful Joe. As soon as I get to him I’m going to hold him in my arms and never let him go. I shouldn’t have run away. I know that now. I should have stayed and faced up to what I’d done, but I didn’t and this is my punishment.

Joe’s voice is growing fainter and I’m no longer sure which direction it’s coming from. Then a loud bang penetrates the air and a noise like a siren starts up, its wail so loud I have to cover my ears. But as I do so I feel something crack me on the back of the head. Pain like nothing I’ve ever experienced before spreads across my skull. The siren gets louder and louder in tandem with the pain, so loud that it drowns out Joe’s voice completely and the white world turns black.