Becca does it. The others were taking for granted it would be Holly or Selena, in case the nurse notices the key gone missing; Holly is the best liar, and no one ever thinks Selena’s done anything wrong, while Julia is always one of the first people teachers think of, even for things that would never occur to her. When Becca says, ‘I want to do it,’ they’re taken aback. They try to convince her – Selena gently, Holly delicately, Julia bluntly – that this is a bad idea and she should leave it to the experts, but she digs her heels in and points out that she’s even less likely to be suspected than Selena, given that she genuinely never has done anything worse than sharing homework and everyone thinks she’s a huge goody-goody lick-arse, and that might as well be useful for once. In the end the others understand that she’s not budging.

They coach her, after lights-out. ‘You need to be sick enough that she keeps you in her office for a while,’ Julia says, ‘but not sick enough that she sends you back here. What you want is something she’ll want to keep an eye on.’

‘But not too much of an eye,’ Selena says. ‘You don’t want her hovering.’

‘Exactly,’ says Julia. ‘Maybe you think you’re going to puke, but you’re not sure. And you think probably you’ll be fine if you just lie still for a while.’

They’ve left their curtains open. Outside it’s below freezing, frost patterning the edges of the windowpane, the sky a thin sheet of ice laid over the stars. The shot of cold air hits Becca like it’s been fired straight through the glass from the huge outside, wild and magic, pungent with foxes and juniper.

Holly says, ‘But don’t act like you want to puke. That looks fake. Act like you don’t want to puke. Think about trying your hardest to hold it in.’

‘Are you sure about this?’ Selena asks. She’s propped up on one elbow, trying to see Becca’s face.

‘If you’re not,’ Holly says, ‘no probs. Just say it now.’

Becca says, ‘I’m doing it. Stop asking me.’

Julia catches a glance and the tip of a smile from Selena: See, our shy Becca, this is what I meant— ‘Good for you, Becsie,’ she says, reaching across the space between the beds to high-five Becca. ‘Make us proud.’

The next day, lying on the too-narrow bed in the nurse’s office, listening to the nurse hum Michael Bublé as she does paperwork at her desk, Becca feels the wild cold of the key strike deep into her palm, and smells running vixens and berries and icy stars.