The floorboards creak above me as Jake walks from his room to the bathroom. My fingernails fill with crumbs as I search down the side of the sofa but there’s still no sign of my phone. That means it’s either down the side of the armchair or it’s in my handbag in the kitchen. I head for the armchair and yank at the cushion.

A phone flips onto the base of the armchair. It’s an iPhone, but it’s not mine. It’s a newer model. I press the circular button at the base of the phone and the screen flashes to life revealing a preview of a new message. Even though the phone is locked I can still read every word of the short text:

I can keep a secret if you can.

Chapter 35

Where am I?

WHERE AM I?

It is dark. Pitch black. I can’t see anything.

‘Jake!’ I scream his name. ‘Mark!’

No one comes.

I shout again. ‘Someone please help!’

The sound reverberates around me.

‘Hello?’ The word catches in my throat. ‘Can anyone hear me?’

My hands shake as I lift them from my lap and tentatively extend my arms. I grope around in the darkness, swiping at the air. There’s nothing, nothing, and then the fingers of my left hand graze something cold and solid and I snatch my hands back to my chest. As I do something sharp pricks at my stomach. It’s in my lap! I swipe at it and jump away. My back smashes against a wall and my heels skitter on the ground.

There is a clattering sound, like metal hitting tile, and I freeze.

I want to shout for help but I can’t. I can’t speak. I can barely breathe.

My bottom feels cold and wet, as though liquid has soaked through the seat of my jeans and onto my skin. The air is thick with the scent of urine and iron.

I need to calm down. If I don’t I’ll pass out.

I concentrate on my breathing, sucking in air and filling my lungs before I blow it back out again.

In. Out. In. Out.

Slowly, slowly, my breathing quietens and my fingernails, gripping the wall I’m pressed into, cease their incessant tapping.

‘Hello?’ The word echoes off the walls. I am in a room, an empty room. I touch my fingertips to the ground beneath my feet. The walls and floors are tiled.

Okay. Okay. I’m in a room. I’m on my own. There has to be a door or a window, a way out.

As my heartbeat slows, the darkness surrounding me seems to fade and objects emerge from the gloom. There are two sinks to my right, two cubicles to my left and a metallic urine trough on the other side of the room. Beside it is a door, with a sliver of light at the bottom.