‘Naomi! Naomi!’ my sister screams from somewhere far away. I run to where the sound is coming from, but just as I see her standing at the end of a long corridor, dressed in her white nightie and holding her pink bunny rabbit, a door slams shut in my face.

My eyes snap open, desperately searching the darkness for proof that that didn’t really just happen. I force my breath under control and roll onto my back, waiting for the ornate ceiling rose above our bed to emerge from the shadows.

There’s a noise, much like the slamming door in my dream, but further away and fainter. My ears prick up like a dog’s on guard, waiting to hear it again. I’m trying to still the thump thump thump of my heart, as it competes with the underwater noise that is rushing around in my ears.

I need to separate reality from the nightmare, but my thoughts and terrors are all metamorphosing into the same thing.

It’s the tiniest of sounds, but one I know so well; the slow, unavoidable creak of the third stair from the bottom, as it bows under the weight of even the lightest foot.

I throw a hand over to Leon’s side of the mattress, hoping to find his sleeping body, rising and falling with his silent breath. But the bed is empty and the sheets are cold. I sit up, trying to force my brain to track back to last night. Had I dreamt that Jacob had gone missing? Had Anna really threatened to kill herself? Had Leon and I resolved our row? A heap of thoughts crowd my brain and I tick them off one by one. No, yes, no.

Leon had been asleep when I came home – at least he’d pretended to be – so as I come to, the knowledge that we’ve still got to iron out our problems instantly gnaws away at me.

Knowing I won’t be able to go back to sleep until he’s in bed beside me, I pull on his t-shirt, which is balled up on his pillow. If I’d thought about how strange that was – Leon always sleeps in his t-shirt – I would have perhaps known that all was not well. But the benefit of hindsight is a wonderful thing.

There’s a noise again.

I tiptoe to the bedroom door and stare out into the darkness of the landing, listening for a clue as to where he is and what he’s doing. There’s nothing but silence.

I peer over the banister to the hall below, hoping to see a glow of a light creeping up from the kitchen where he must be making a cup of tea, but the house is cloaked in shadows.