Standing on the bed, I grope for the hatch above my head, and then insert the blade of the Stanley knife and run it around the rim, trying to clear it from dirt and debris. My shoulder is already aching. Dust clogs my throat, and sweat trickles into my eyes as I work at the seam of the cover with the rusty blade. I can’t find any screws holding it in place, and unless it’s locked from the outside, it should pry loose, but despite my best efforts, it doesn’t budge.

‘Do you want me to try?’ Peter says, his voice small in the darkness.

I doubt he’ll succeed where I’ve failed, but I need to keep him occupied. And he has two hands to my one.

‘Can you climb up here next to me?’ I ask. ‘Careful now. That’s it. OK. There’s a sort of manhole cover above our heads, Peter, and I want you to see if you can push it open with both hands. It’s really stiff. I’ll need to lift you up for you to reach it.’

‘But I can’t see!’

‘Feel your way. Come on, Peter. You can do this.’

The throbbing in my left hand intensifies as I lift him up. My palm feels hot and inflamed: the beginning of an infection. If I don’t get antibiotics soon, sepsis will spread through my body and kill me, but I’m not worried: there are plenty of other ways for me to die down here first.

‘It’s stuck,’ Peter pants. ‘I can’t move it.’

‘Try again.’

Peter bangs on the hatch with his fists, dislodging dirt onto the two of us. ‘Help!’ he shouts. ‘Help! Can anyone hear us?’

I cough. I feel dizzy and light-headed from a combination of concussion and blood loss, but I can’t afford weakness now. ‘Save your breath, Peter. Hitting it won’t help. See if you can loosen the cover at the edges.’

‘It’s jammed, I told you,’ he says, banging the cover again. ‘Help! Someone help us! We’re stuck down here!’

‘There’s no point shouting,’ I say. ‘No one can—’

And then we hear it.

A familiar voice, faint but clear, calling my name.

‘Harper!’ I shout. ‘Peter, jump down. Harper!’

‘Millie!’ she yells. ‘Millie, where the hell are you?’

‘We’re in a cellar!’ I shout, thumping against the pool hatch. ‘Stacey locked us down here!’

‘How do I get to you?’

‘There’s a door at the end of the hallway upstairs,’ I shout. ‘It’s hard to find—’