Shivering, I curl into a ball and rub my arms while the sea pounds against the rocks outside and the wind answers with a mournful lament. The lamplight flickers at the edge of my vision, but I don’t look at the shadows. I can sense them, though, shifting around me, the darkness growing stronger.

After a few minutes, Tom’s breathing slows and becomes heavy, tiredness seeming to get the better of him. I stare at the shape of his back under the covers, hoping that his sleep is dreamless and wishing I could have told him how I feel. A ball of emotion swells in my throat and I try to push it down, but it only gets bigger.

The room darkens. I raise my head and check the oil lamps, thinking they must have gone out, but they’re burning the same as before. And then I realise – it’s not the light that has dimmed. The darkness itself has grown stronger. It crowds around my bed like a mob of people, the black shapes blotting out the lamps and glow of the lighthouse. I can feel the darkness pressing down on me like it has an actual physical weight.

Squeezing my eyes shut, I whisper, ‘I’m sorry, Tom. I should never have asked you to come to the island with me, and now we might never leave.’ I release a shuddering breath. ‘I should have told you everything, but I didn’t want to scare you. I didn’t want to see the panic in your face, knowing it might be the last time I ever saw you.’

The darkness is like a hand around my throat.

I have to get the words out; I have to tell him the truth before it’s too late. My voice shakes, but I don’t stop. I tell him everything that’s happened since we were in the lighthouse – about the cormorants smashing through the windows, and meeting Morgan, about the witch inside me and how Merlin killed her, and how I have to train with the others so they can enter the portal. I tell him about my failed attempt at turning into a bird, and how the demons are in the house and could take physical form.

I open my eyes and the darkness has receded as if whatever was there has taken several steps back. My throat is dry, but I carry on talking. ‘You’re right, I am afraid. Not just of what’s in the shadows. I’m afraid that whatever it takes to become a witch, I won’t be able to do it. I’m afraid that my mum will die in a cage and Morgan and the others won’t be able to go home. And I’m afraid of losing another friend, knowing it was my fault.’