No, witches aren’t real. They don’t exist. It must be Tom’s snoring, or the muffled crash of waves. Keeping the covers clamped over my head, I tell myself that I’ve been silly to believe my mum’s stories. Witches aren’t real. I repeat the thought over and over until my brain stumbles over the words and I fall into a shallow sleep potholed with nightmares.

When I open my eyes, daylight is streaming through the window and Tom is sitting on the bed opposite, looking at me intently. I wince and shield my eyes. His face is preferable to that of a witch, but it’s still unsettling to wake up and see someone staring at you.

‘What time is it?’ My voice sounds raspy and I clear my throat.

‘Nearly noon. You OK? It sounded like you were having a bad dream.’

I sit up and rub my head, trying not to think about last night. And then I remember the figure I saw on the landing. That part wasn’t my imagination, it was real.

I glance behind him and notice my bag is on the bed, next to his stuff. He sees me looking and scratches his cheek. ‘I packed your things. I didn’t think you’d mind.’ He sounds worried, but I’m not angry. If anything, it makes me feel sad. It’s not like I had much to pack, and as coercion goes it’s a pitiful attempt. Something a kid might do.

A sigh escapes me. ‘Tom, I know you think I –’

He stands abruptly. ‘Just come and see David with me. You can make up your mind after you’ve talked to him. If you decide to leave, then you’ll have your stuff with you.’

‘But –’

‘Please, Ivy. Just talk to him.’

‘OK, fine.’

He smiles and I look away, feeling uncomfortable. I’d already decided to see the boatman, though not for the reason Tom thinks.

He grabs his washbag and heads for the door. Once he’s gone, I get out of bed and notice something on my pillow – a book. I’m not sure how it got there, or how I managed to sleep without rolling into it. The cover is faded, the title embossed with silver letters that have lost their gleam. The Life of Merlin. Tucked inside is a long cormorant feather.

I open its pages and it smells old and fusty, the yellow paper crammed with tiny print. I don’t know much about Arthurian legend, but I thought it was fiction – the characters and events made up rather than based on history. Yet the footnotes are full of dates and locations, as if the feasts and battles actually took place.

The feather marks a chapter near the end: ‘Merlin’s Dark Desires’. I scan a few paragraphs and then come to a line that makes my stomach drop.

Merlin was able to resist his demonic nature (1) throughout most of his adulthood, but that was to change at the end of his life if various accounts are to be believed.