“I’m okay,” said Noor faintly after a few minutes. She’d wiped her mouth and chin, but there was still scarlet-flecked slime on her PE top. “I’m okay. It’s fine.” There was a certain kind of teenage girl who would claim everything was fine up to and past the end of the world. The other option, of course, was sobbing hysterics, which would not have been unjustified. Possessed by a third-order demon—at school. Where she should have been safe. Where they all ought to be safe. Walden did not let her feelings show. She was furious with herself.

There was a sound from the doorway. Walden looked up. The duty Marshal stood there, with his sword half out of its sheath. “Perfect timing,” she said. “We’ve had an incident. Please could the Marshals do a full check of this room, and then—are you both boarders?” The children nodded. “Sweep Scrubs, please. Starting in the Year Nine dormitories. Thank you. I’ll join you shortly. If Mr Daubery is on site, do please alert him as well.”

Walden was busy with incident response for the rest of the day. The Marshals unearthed one culprit quickly enough: Alfie’s dormitory had a second-hand, unauthorised Nintendo Switch hidden in the back corner of a wardrobe, apparently held in common by all six boys, actual origin unclear, exactly the sort of device that an imp might find irresistibly attractive as a dwelling place. Once he’d been cleared by the nurse, Walden delivered a blistering tongue-lashing first to Alfie individually and then to the six of them as a group. Two weeks of daily detention. No clubs, fixtures, or extracurricular activities. The Head would be calling their parents. The boys hung their heads.

Class clown Morris came back to knock on Walden’s office door afterwards with an additional confession: the Switch was his idea. He’d found it on eBay. It was all his fault. So that needed another tongue-lashing, and an additional punishment, but this had to be tempered with a measure of approval for Morris’s honesty and obvious agony about the whole thing. Walden was not surprised that her first instinct had been right, and he was mixed up in the trouble somehow. You got a feel for these things.