‘Looks like we’re in,’ she says.

Our feet pound against the concrete stairs. We reach the top floor. My heart is thumping but it’s not just exertion making it race. It’s fear.

‘Marie?’ I knock on the door but my gloves muffle the sound and so Carly raps with her knuckles instead while my fingers spider-crawl across the top of the door frame, hoping that it’s still there.

It is.

‘Spare key.’ I slot it in the lock while Carly rolls her eyes and mutters about security.

The smell hits as soon as I open the door.

‘Marie?’ I call into the stale air and dust, somehow knowing that she won’t answer.

There are only four rooms and it doesn’t take us long to conclude she isn’t in any of them.

‘Something is wrong.’ I know it deep in my gut. The mug I had left here two days ago is still on the coffee table. Still half-full of grey tea. The plate of biscuits I had carried through, stale.

Back in the kitchen I see the washing-up piled in the sink is exactly as it was, crusted baked beans line a saucepan, the frying pan coated with burned egg.

‘It’s as though she left after our visit and never came back.’ Momentarily I cover my nose with my hand. The overflowing bin is pungent. ‘I’m going to check the bedroom.’

I really don’t know what I’m checking for as I yank open drawers and rifle through Marie’s belongings. It feels as though I’m intruding as her underwear, black and lacy, spills out onto the floor; the sort of things I’ve never worn, even before I’d had Archie. There isn’t a wardrobe, the room is too small for that, but there are clothes piled everywhere; on the rickety chair by the window, on the bed that clearly hasn’t been slept in. It’s impossible to know whether anything is missing. My stomach convulses as I realize I no longer know my twin well enough.

‘I’ve found something!’ Carly shouts from the kitchen. I hurry back through.

‘Look.’ She thrusts a notebook towards me. On the top page is scrawled in Marie’s handwriting: Stand-in for lead. Broken ankle. Leave tonight. Six-week run! Circled around each sentence are flowers and hearts. I remember the way her schoolbooks were always covered in doodles.

‘So she’s just… gone?’ I shake my head.

Carly shrugs. ‘It seems that way.’ She looks as upset as I feel.

‘But it was only a couple of days ago we saw her. We got on so well. She promised she’d see more of us. Archie.’

‘If she got a call for work we can’t blame her for taking it. Remember her phone kept ringing while she was here? We know she needs the money.’

‘She’s left her washing-up. The mugs in the lounge.’ I open the fridge. There’s a half-empty carton of milk and some drying ham. Two cans of cherry Coke. The sight of the logo makes me feel ill. How can she bear to drink it? To remind herself? Or is she punishing herself? Still, punishing herself.