“Of course. I don’t know who yet,” said Walden. The truth was she was unlikely to find out, unless someone developed a strong enough guilty conscience or a stupid enough urge to boast. “But most likely a Year Nine or Ten.”

“Sixth form all too goody-two-shoes to vape in the locker rooms?”

“Sixth form have off-site sign-out privileges,” said Walden drily, “and so they go and vape in the woods on the other side of the rugby pitches.”

“Tut, tut. Kids these days. We just did cigs and White Lightning.”

Walden remembered, suddenly and with extraordinary clarity, the taste of the cheap cider Charlie had got hold of one half term—using his last exeat card to catch the train to Luton, flashing his unconvincing fake ID at a corner-shop clerk who almost certainly hadn’t cared in the least, sneaking the big blue plastic bottles back to school and hiding them in a hollow tree stump in, yes, the glade in the bluebell woods on the far side of the school sports fields. White Lightning! It tasted like bad apple juice and adolescent stupidity. The vividness of the taste-memory was a shock. “They don’t sell it anymore, you know,” she said, to chase the thought away.

“What, White Lightning? Really?”

“Discontinued in 2009. Because of,” she allowed herself a thin smile, “the strong association with underage drinking.”

“And just like that, I’m an old man!” said Mark. “I can hear my joints creaking already. Well, listen. I’m not just here to write a report for the governors. Though I’ll do that, and you can think of it as me making your life easier, because it’ll get them off your back. But I’m not planning to spend all my time sitting around taking up office space. Do you do a regular planar patrol here?”

A planar patrol involved creating a temporary portal to the demonic plane and sweeping the area clear of medium-sized demons. It was a lot of power expended for, in Walden’s experience, not very much useful effect. But when Mark said it she saw, irritated, that now Old Faithful was gone—and who-knows-what would be starting to move into its abandoned territory—it was probably a good idea. With any luck, it would prevent nasty surprises entirely. “Not regular, no,” she said, “but I agree that it would be worthwhile to add it to our system, for the time being.” Part of her was already groaning. Planar patrols could not be dumped off on junior Evocation teachers. Adding it to the system meant adding it to Walden’s own overloaded plate.

“Not much of a delegator, are you?” said Mark. “I just told you I’m not here to sit on my backside. Look, is it that you don’t trust me?”

A beat. “Well, I didn’t hire you,” said Walden.

Mark laughed. “Need to see me in action? All right. Are you free Sunday afternoon?”