“It’s always spooky doing this,” Mark said. “No one home? Good stuff. Let’s check the shed.”

He trudged over formless grey towards the land-water boundary, the school boundary. Walden watched without comment as he tried to step back onto what was, in the mundane world, school grounds. The external wards flared briefly golden. Mark sprang away, swearing loudly.

“I think you forgot your staff lanyard,” Walden said. “You were given a staff lanyard to wear on site—weren’t you?”

“Bloody buggering— What?”

“I picked up a guest pass from reception, just in case.” She had it in her raincoat pocket. She fished it out and tossed it over. Mark caught it handily, turned it over to see the holographic outlines of detailed spellwork on the back, and said ruefully, “Daubery fails the test.”

“No, the portal was very good,” Walden said.

He was still examining the pass. The spellwork was Walden’s own, an original design. “This can’t be doing much to keep out demons.”

“There’s more to school security than managing the demon problem. What you just bumped into is actually aimed at unscrupulous human beings.”

“Do you get those often?”

“As with demonic incursion,” Walden said, “the way to assess risk to children is to decide not how often a bad thing happens, but how serious the consequences would be if it did happen.”

“So you’re talking, what, stalking, kidnapping—”

“Honestly, when an unwelcome adult tries breaking into the school grounds, the goal is usually simple theft,” said Walden. “I sometimes think the ICT suite might as well have a target painted on it. But the things you mention are among the worst-case scenarios, yes.”

Mark put the guest lanyard on. “Right. Boundary walk, then?”

“Let’s get going.” Walden crossed the external wards—feeling the welcoming shiver of her own spellwork passing over her, assessing her for belonging, and tidily identifying her as staff—and paused to take in the transformation. From formless foggy pastel, the ground underfoot went abruptly and violently green. The greenery was not grass but the idea of grass, the memory of it, the decades and decades of mowing and rolling and raining and trampling and browsing geese and shouting children. It looked like the brushwork of some abstract painter, which made it quite unnerving to stand on. Mark whistled. “Hear that?”

The shouting: young male voices, mostly, as Walden would have expected. Blurred running figures moving in the green distance. The demonic plane here was shaped by the school. It was not quite as clearly defined as the incursion in School House; but then, School House had been the site of a student boarding house for most of the last five hundred years. “I wonder when rugby was invented,” she said.

“In 1845,” said Mark. “At Rugby. Rugby School, that is.”

“Less than two centuries, then,” Walden said. “But I suppose we have been playing a lot since then.”