She would not normally have shared this titbit with the group. She was immediately annoyed with herself, because she knew she’d said it to impress Kenning. Why did she need to impress Kenning? Kenning was just a rather difficult colleague. But Walden couldn’t resist glancing over, trying to gauge the effect of the boast: I am considerably more knowledgeable about demons than you, and I have the alarming job offer to prove it.

Kenning appeared to be looking out of the lab window. She probably wasn’t even listening.

But the sixth formers were. “Wow,” said Will.

It was too late to unsay it. Walden resigned herself. “Were they scary?” said Mathias, clearly envisioning some sort of gun-toting, sunglasses-wearing hit squad.

“Not at all. When Americans are trying to recruit you, they are extremely nice to you.” Walden remembered the recruiters—a man and a woman, both in conservatively cut suits—offering plums one after another: funding, unlimited; never worry about research grants again; lab space, state of the art; opportunities for promotion; no need to relocate, there’s a California campus; fieldwork, of course not, unless that’s a direction you’d like for your career; and then the final twist of whipped cream on the military-thaumaturgic trifle: Considering your relationship with Dr Chan—how pleased they’d been with their munificence, and their frightfully modern and relaxed attitude to lesbianism—eventually, we’re sure you’ll be thinking about citizenship.

Walden had said she would think about the offer. And then she had booked a flight back to the UK. Her relationship with Rosalind Chan had been dying already; doomed, really, since the day Roz said to her, Honestly, Saffy, I think babysitting is beneath you. You’re too good to waste on high schoolers—and what’s a schoolteacher anyway but a failed academic?

Back at home, the Ministry of Defence had never approached Walden, though she’d been half expecting it. Presumably the MOD had a plentiful supply of people like Will’s uncle. Or perhaps they’d just found out that she’d said no to the Americans, and felt they couldn’t top that offer on a civil service budget.

“All right, that’s enough of that,” she said, before the class could dive any further down this particular personal history rabbit hole. “Let’s summon a demon, everyone.”

They took up positions around the five-pointed array—pentagrams were a classic for a reason, one of the safest and simplest of all the summoning forms. Walden joined them, placing herself at the northern point of the pentagram so that she would be able to anchor the students if necessary. “I’ll demonstrate good form for you again, and then we’ll go one at a time,” she said. “Everyone ready?”

Nods, mumbles; a clear “Sure!” from Nikki. In the corner of the room, Kenning shifted position subtly, though her arms stayed folded.

“On my count. Three—two—one—”