‘We have been reassured that the police are making extraordinary efforts to ensure your classmate is returned safely.’

A crackle rises at the mention of the police. Mrs Christie meets it head-on. She grips the edges of the lectern in full power-stance mode.

‘You would have seen the media at the gates this morning. I don’t need to tell you that we expect every student here to demonstrate their maturity and refrain from talking to reporters. If you have any important information, you are urged to talk to the police. Reception will take your names, and they will contact you directly. LET. US. PRAY.’

Hundreds of heads drop. Mrs Christie prays in the same voice she uses to talk about skirt length and bags left out in the corridors. She hasn’t said Yin’s name once. I suppose she wants to keep us under control, more than anything. As if we’ll erupt into hysteria at any moment. Which we might.

I keep my head up and my eyes open as the prayer drones on.

Most girls lower their heads and close their eyes, even though I don’t believe for a second that all of them are religious. The fence-sitters drop their heads but keep their eyes open. Only a small number rise above the crowd, and they’re not the popular girls or the chronically rebellious. They’re the nerdy girls and the quiet girls, girls who practise other religions and atheists like me. Yin was one of us.

I glance down my row and see Petra’s lips moving frantically. Her eyes are squinched shut; she’s praying as if her life, not someone else’s, depends on it. Even though I’m not a believer, there’s something beautiful about how her faith shows in her face, like there’s a small light inside her. If it wasn’t completely inappropriate and intrusive, I’d like to take a photo of her now, capture that look.

I try not to act surprised when Petra speaks to me in the corridor, as if she somehow sensed me watching her during prayers. The first bell rings around us. Our lockers have been side by side all year, yet we’ve never done much more than nod hello.

‘They didn’t even like Yin,’ Petra whispers around her locker door. ‘I don’t know why they have to make such a scene.’

The scene is most of 10S sitting on the floor in a red-eyed, sniffling heap. Teaghan is hiccup-crying loudly. They look genuinely upset, although I notice one or two girls looking up occasionally to check that everyone is noting their distress.

I wedge my foot under my locker door to stop it from swinging too far open. My phone jitters on the top shelf. I don’t even need to look at the screen to know that it’s yet another episode in the Morrison High meltdown. Liana and Katie have even got the boys messaging me, telling me to come back.

‘They never paid any attention to her,’ Petra says. ‘And now they’re carrying on as if she was their best friend.’