Something blue-white zips along Holly’s bones. The face on Joanne as she held out that screen, tongue-tip curling, wet-fanged at the delicious thought of doing damage. The way she licked up the shock Holly couldn’t help showing, every drop. Joanne would do bad stuff, stuff that comes from places most people would never know how to imagine.

Don’t worry. We’ll get him.

Holly knows how to imagine the places where bad stuff begins. She’s had practice.

‘What the fuck?’ says Julia, craning against her shoulder. ‘There’s people in the bushes, look.’

Off in the haze of layered greens beyond the grass, a flick of white. Like Technical Bureau boiler suits.

‘They look like they’re looking for something,’ Selena says, leaning in at Holly’s other side. Her voice has that floppy, hard-work sound it’s had for the last couple of weeks; it gives Holly the plunk of guilt she’s starting to get used to. ‘Are they police too? Or what?’

Other people have noticed: excited jabber is filtering through the walls, feet go thumping down the corridor. ‘Maybe some guy was running away from the cops and he threw something over the wall,’ Julia says. ‘Drugs. Or a knife he used to stab someone, or a gun. If only we’d been out last night. Now that would’ve made life more interesting.’

They don’t feel it, what’s prickling at Holly’s scalp. The tug in the air has hooked them – Lenie is buttoning her shirt too fast, Jules is bouncing on her toes as she leans against the window – but they don’t understand what it means: bad things.

Trust your instincts, Dad always says. If something feels dodgy to you, if someone feels dodgy, you go with dodgy. Don’t give the benefit of the doubt because you want to be a nice person, don’t wait and see in case you look stupid. Safe comes first. Second could be too late.

All the school feels crammed with dodgy, like cicada noises zizzing through a hot green afternoon, so shrill and many that you’ve got no chance of picking out any single one and seeing it straight. Joanne would go a long long way to get Selena in bad trouble.

I don’t get pissed off with people like her. I get rid of them.

The bell for school goes. ‘Come on,’ Becca says. She hasn’t come to the window; she’s been plaiting her hair in a calm methodical rhythm, like there’s a pearly bubble of cool air between her and that fizz. ‘You guys aren’t even ready. We’re going to be late.’