‘The shadows are demons?’

He nods and continues. ‘Demonic possession can have a mild or catastrophic effect on the host. This can include repetitive movements, such as twitching of the facial muscles or violent jerking of the limbs.’ He turns the page. ‘When a demonic entity is in between hosts, it can be seen as a dark shadow.’

Realisation closes my throat.

‘Maybe that’s what your mum thinks she’s protecting us from.’ He huffs and adds, ‘It’s what she thought was inside me.’

A creak sounds on the landing and we turn and look at the closed door. It comes again, slow and drawn-out, as if someone is trying to move quietly.

C-r-e-a-k.

Tom frowns at me and mouths, ‘What’s she doing?’ and I shake my head.

He eases the blankets off and I wave at him to get back into bed, but he goes to the door and drops to his knees. He’s going to look through the keyhole. I imagine my mum outside, sprinkling salt or wafting around smoke, and feel a surge of protectiveness towards her. Whatever she’s doing, I don’t want Tom to see.

I throw off the covers and swing my feet to the floor. ‘Just leave it,’ I hiss.

Ignoring me, he puts his eye to the keyhole and it comes again.

C-r-e-a-k.

And then there’s a different noise: a slow screeching sound as if someone is running their fingernails down the door.

He jumps back and stares at me.

‘What is it?’ I whisper. ‘What’s she doing?’

‘She’s … she’s not there.’ He blinks at me in disbelief. ‘There’s no one there.’

‘What?’

He rakes his hand through his hair and stares at me, dumbfounded. ‘But I heard her. She was outside.’

I push him aside and peer through the keyhole. All I see is the shadowy landing. ‘It’s dark; maybe you just didn’t see her.’

‘But she was right there. I heard a noise and the door moved. I felt a rush of air, I should have seen something.’

He looks at me as if expecting me to have the answer, but all I can do is shrug. If it wasn’t my mum, then I don’t want to think about what was scratching at the door. Gathering my courage, I pick up a lamp. ‘I’ll go and speak to her.’

The floorboards creak ominously as I step onto the landing, but there’s no sign of her. ‘She must still be up here,’ I whisper. ‘We’d have heard if she’d gone downstairs.’ I walk to her door, then pause and listen.

‘Is everything OK?’

My mother’s voice comes from nowhere. I turn and she’s standing at the bottom of the stairs, holding up a lamp. Her long blonde hair is more dishevelled than ever, her eyes two shiny black buttons in the dark.

‘Tom – well, we, thought we heard something.’

Her fingers flutter to her throat. ‘What did you hear?’ I glance at Tom and she adds breathily, ‘You must tell me if you see or hear anything.’ The fear in her voice sets my nerves on edge. I’m about to tell her, when Tom cuts me off.