“Boyfriend,” said Walden. “We were going to attend Leavers as a couple, actually, which in sixth former seriousness terms is only a few steps down from getting engaged. God knows what would have become of us at Oxford. Probably broken up by the end of Michaelmas term of first year.”

Laura said, “Oh,” and then, after a moment, “I thought you were…”

“Bi,” Walden said. Despite her best efforts, she felt her mouth twitch with amusement.

“Right,” said Laura, looking embarrassed.

“My turn for a question,” Walden said. “Why are you working for Chetwood? I mean, not to put too fine a point on it, you’re obviously extremely good, and it’s—”

“—a career dead end,” Laura said. She wrapped both hands around the WORLD’S BEST TEACHER mug. “I know. Everyone told me. Nicola Conway.”

“What?”

“Nicola Conway is why,” Laura said. “Or, well, not exactly. She doesn’t remember me. But the Conway case—I was there. Twenty-two years old, still a junior, barely knew what I was doing—but I was there. Whole family dead in a surprise incursion. Absolutely bloody awful.”

“I see,” said Walden, who didn’t.

“The thing is that it was our fault,” said Laura. “The Marshals. Oh, not officially, of course not officially, but there’s a screening program in primary schools and we should have picked up the Conway kids and had tabs on them long before it got to that point. It was both of them, you know. Nicola and her brother. I went through the records afterwards. I was strongly encouraged not to, but I did.” She made a face. “And we had Nicola on the record as one to keep an eye on—she must have been what, Year Two? And tested top of the range every year. Her brother had only just started Reception, but given Nicola’s scores, we should have been keeping an eye on him as well. But they were both out sick with a stomach bug the week the Marshals visited their primary school that year, and no one followed up. The Marshals should have done it, but they left it to the teachers to organise, and the teachers were too busy to bother. Inner London state primary, you know.”

Walden knew. Teaching was a hard job, but the version of it she did—reasonably well-paid, comfortable, straightforward, with the vast majority of students from overwhelmingly well-off backgrounds and speaking fluent English—all this was a breeze compared to the challenges many schools faced. She could see very easily how Nikki and her brother had fallen through the cracks. But at what cost?