Before lights-out they lay out their clothes on their beds and start getting dressed. Layers of tops – outside the window, the night sky is clear and frozen; sweatshirts; heavy jeans; pyjamas to go over it all, until the moment comes. They fold their coats away under their beds, so they won’t need to rattle hangers or squeak wardrobe doors. They line up their Uggs by the door so they won’t have to fumble.

Now that it’s turning real, it feels like a game, some geeky role-playing thing where someone will give them fake swords and they’ll have to run around smacking imaginary orcs. Julia is singing ‘Bad Romance’, cocking a hip and whirling a jumper by one sleeve like a stripper; Holly joins in with a pair of leggings on her head, Selena whips her hair in circles. They feel stupid, and they’re turning giddy to dodge that.

‘Is this OK?’ Becca asks, spreading her arms.

The other three stop singing and look at her: dark-blue jeans and dark-blue hoodie, the hoodie stuffed spherical with layers and the hood strings pulled so tight only the tip of her nose shows. They start to laugh.

‘What?’ Becca demands.

‘You look like the world’s fattest bank robber,’ Holly says, which makes them all worse.

‘You’re twice your size,’ Selena manages. ‘Can you even move in all that?’

‘Or see?’ says Julia. ‘That’s just what we need: if you can’t make it down the corridor without smacking into walls.’ Holly does Becca, lurching along blinded and unwieldy. The giggles have hold of all three of them, the helpless kind that keep going even after you run out of breath and your stomach muscles hurt.

Becca has gone red. She turns her back to them and tries to get the hoodie off, but the zip is stuck.

‘Becs,’ Selena says. ‘We’re only having a laugh.’

‘Whatever.’

‘Jesus,’ Julia says, rolling her eyes at Holly. ‘Chillax.’

Becca yanks at the zip till it dents her fingers. ‘If it’s just a great big joke, then why are we even bothering?’

No one answers. The laughter has faded to nothing. They glance at each other sideways on, eyes skidding away from meeting.

They’re looking for a way to ditch the whole thing. They want to throw their clothes back in the wardrobe, bin the key and never mention it again, blush when they remember how near they came to making idiots of themselves. They’re just waiting for someone to say the word.

Then one of the second-floor prefects slams their door open, snaps, ‘Stop lezzing it up and get changed, it’s lights-out in like five seconds and I will so report you,’ and bangs the door closed again before any of them can shut their mouths.