Volume fourteen of the Dorking Record contained the earliest evidence of Old Faithful on the school site. “‘On this day the great demon returned & consumed two wizards entire,’” Philomela read aloud with relish. Walden couldn’t actually manage Dorking’s handwriting, but she’d seen a transcript before and that sounded about right. “‘Wizard’ rather than ‘magician,’ because we’re before the nineteenth-century academic movement. Interesting that it’s ‘returned,’ isn’t it?”

“Does that mean it’s been here even longer than that?” asked Kenning.

“Almost certainly!” said Philomela. “Now, let me see what else I can find for you.”

Filing cabinets, straining cardboard boxes, old wooden travellers’ chests. Walden and Kenning stood close together in the one clear patch of floor in the middle of the archive as Philomela darted around them. The slatted blind on the skylight gave Kenning’s short fair hair a zebra stripe of light and shadow. She looked uncomfortable. “Letters from schoolboys,” said Philomela, “bills for repairs; here’s the deed of gift from the Worshipful Company of Brewers, which of course is how the school could afford to build the thaumic engines—and Brewers Hall to put them in, naturally. There’s still a Brewers scholarship every year. Now once you get to the twentieth century things get a little interesting—this is a letter to The Times from 1913 that mentions a ‘greater demonic power’ in the context of Chetwood School—you can see the contemporary politics behind it, because of course we’re building up to the First World War and everyone has started thinking about demons as weapons…”

“What about incursions?” demanded Kenning.

“If I may,” said Walden, and pointed. Philomela gave her hands an assessing glance—they were clean, of course—and then handed her the stiff folded card. Walden showed it to Kenning. “The order of service for a funeral,” she said. “Rodney Merringham. The Headmaster who died in 1926.”

“We actually don’t know very much about him!” said Philomela. “He was an alumnus, of course—there have only been a handful of non-alumnus Headmasters, our current Mr Bern among them. And like practically all Englishmen of his generation, he was a survivor of the trenches. Most of his contemporaries from school were already dead—you’ve seen the memorial board in the chapel, haven’t you?” She took the funeral order of service gently from Walden’s hands. “He was quite young, only forty-something. And people were rethinking it all in the twenties—arcane safety, as they say now—after everything that had happened during the war. I’m sure it must have influenced his decision to try to destroy Old Faithful. Of course he failed. Technically this was for a memorial service, not a funeral. There was no body found, you see. That’s a common thread in Old Faithful’s incursions. Here’s the next one.”