“Mum and Dad are too busy to be much use,” she says. “No, we should go straight to the Marshals. Because when the big one—” She stops. She is not a coward. She looks at Nikki. “When Old Faithful tried to break through,” she says, “it was Marshal Kenning who went in, wasn’t it? So if we want someone who understands … we want Marshal Kenning. I did some research and I think she’s in London, at the Brixton chapter house. It’s on the Victoria Line.” She waves the phone screen at them again as proof.

Mathias unhunches. He is almost unaware—they are all almost unaware—that he is actually the tallest of the four. “Yeah,” he says suddenly, urgently. “Yeah. Because of the—”

He loses the word he wants. A hopeless hand gesture is all that takes its place. Think it through, take your time, you would say, if you were teaching this lesson. You are not there now. Anything you have taught them, they will have to apply by themselves.

“Because woo I have such magicky feelings, right,” says Will, and then—to everyone’s surprise including his own; maybe it’s because Nikki is there—“sorry, Matty, I’m a dickhead. You’ve got something, haven’t you.”

Mathias is starting to sink back into himself again, but he nods. “There’s a thing,” he says. “There’s like a—a thread. Sorry. It’s probably woo.”

“No, it’s not,” says Nikki decisively. “Tell us.”

“Like a—line,” Mathias says. He struggles, struggles, for technical vocabulary. You set them tests on this in Year Twelve. The terminology of academia may seem like an obstructing wall of jargon—and sometimes, perhaps, it is—but far more often than that, it is a set of keys. You cannot understand the forces you are dealing with, still less wield them meaningfully yourself, unless you have the words to set around them. The language of power is the handle on the knife.

Mathias wrestles his way through sentences like a person hip-deep in mud. He has an enormous, near-demonic instinct for how magic moves in the world, and a predicted C grade in his theory paper. It speaks well of the others that they listen with patience to his halting jumble of words. Of course, they know him well; they know that his ‘woo magic feelings,’ as Will terms them, are seldom without merit. After all, they are students at a boarding school together. They might as well be crewmates on a starship, or inmates in a jail. It is a profound, compelled, inescapable intimacy.

At last Mathias hits on the word that unlocks his perception for the rest of them: “—like a binding—”

“Like an oath,” says Nikki. “You mean a geas—an oath.”