‘Mormor?’ My voice is barely a whisper. I reach to turn on the light, but I can’t find the switch. I turn on the torch of my phone and hold it out before me, then lick my lips and swallow. The sound that comes from my mouth is a frightened squeak. ‘I know there’s someone in here. I saw you from outside.’

I scan the kitchen to my right. The oil lamp gutters on the wooden table, its flame casting strange shadows about the room. The little dresser is there with its row of blue flowery crockery. The colourful rag rug is where it should be. Mormor’s books are all in place. The wooden chairs are tucked neatly under the table.

The kitchen smells strange – of boiled potatoes and vinegar. The tap drips with a rhythmic plop. A pan and dirty plates are stacked on the draining board. Mormor would never do that. What’s going on?

My fingers tighten on the strap of my rucksack as I enter the open-plan living room. Embers glow red in the cast-iron stove to my left. It looks sinister in the dark: a pot-bellied monster on stumpy legs. Above it is the painting Mum did of the island, the choppy waves of the sea glinting in the half-light. The blue and white checked sofa facing it is empty. I go to the back of the cabin. Three more rooms: Mormor’s bedroom, the spare room and the bathroom.

I walk on tiptoes, glancing in every direction. The creak of a floorboard makes me freeze. I spin to my left, expecting someone to jump out on my blind side, but there’s just shadows. Forcing my legs to move, I make my way to Mormor’s room. It’s darker on this side of the cabin. I hold out my phone, but it only illuminates a tiny patch of wall. I hesitate outside her door.

Someone is breathing on the other side.

My heart skitters in my chest. I lean my ear against the wood and gasp. There’s a faint shuffling sound.

What if they’re doing something to Mormor? I have to stop them!

My hand trembles as I grasp the knob.

I open the door and scream. A boy is standing there. Tall and wiry, about the same age as me. He has long dark hair, a pale face and wears black eyeliner under his eyes. He stares at me and holds up his hands in a bizarre act of surrender, as if my phone is actually a gun.

Fear turns to rage. ‘Who the hell are you?’ For a crazy moment I think he must be an apparition, not a real human being. But a ghost wouldn’t look so terrified.

‘Sorry! I can explain, please. I can explain.’ He says something in Norwegian, then tries again. ‘Please, it’s not what you think.’