“No,” said Walden. “I imagine the MOD’s file on me is mostly interested in my research history and my time abroad.”

“And how recruitable you are,” Mark said, smiling easily as if he wasn’t almost certainly sharing the contents of a database that needed security clearance to access. “Not very, in case you were wondering, barring a Third World War situation.”

“Funnily enough, I knew that already.”

“What I wanted to say is—I don’t actually meet very many people with principles. Serious principles. But I know you’ve got them. I don’t. Could never stick to any. But I respect it.”

“I seem to remember someone making fun of my career earlier this evening,” Walden said. “‘Teaching a niche A-level’—wasn’t that it?”

Mark shrugged. “Most people with principles are hypocrites on some level,” he said. “It’s just that the level is usually ‘money.’ Puts you a step ahead of the crowd, if for you it’s ‘not being bored out of my mind.’ If you really thought the best use of your time was, what was it, making a nasty world a little bit fairer for all the poor innocent children, then you could be teaching GCSE Maths in some sad inner-city comp, couldn’t you? But you love magic. It’s the magic that keeps you at Chetwood, not the money. So yes, Sapphire, for that, you have one arsehole’s genuine respect.”

“Thank you so much. I’m sure I shall treasure it forever.”

Mark snorted. “And you cut me down to size. I enjoy that.”

“Do you?”

The train rumbled through the December night. It was the slow train, following the old Victorian tracks and stopping at every country station, and there were not many other people left in the carriage. They could have claimed a table by now, but instead they were sitting side by side.

“Of course I do,” said Mark, smiling down at her, and then he took Sapphire’s hand and he kissed her again. He was still a very good kisser.

So she took him back to her flat, the wood-panelled Headmaster’s flat in Brewers Hall next door to the thaumic engines, which rumbled quietly to themselves in the otherwise ghostly silence of the empty school. And they had sex, which Mark was also good at. Sapphire rather wished she’d insisted on a gin and tonic first, just to relax a bit. It was hard not to be self-conscious. It had been a long time. She wasn’t someone who got terribly worried about how her body looked to other people—obviously not, or she would be going to the gym once in a while—but Mark was very fit, and, well, thirty-eight looked pretty different from eighteen.