In 1926 there was a major incursion. Three minor ones followed: 1929, 1935, 1938, and then Old Faithful slowed down after a retooling and expansion of the thaumic engines. In 1961, another major incursion, with two deaths, following an attempt to move Chetwood’s school site across the county. It had turned out that abandoning a centuries-old set of protections was not a good idea. Old Faithful had seized the opportunity, the school had moved back to its original site after the disaster, and the Headmaster had resigned in disgrace. In 1962, a minor incursion, aftershocks. In 1978, another minor. Then a long period of quiet. “By this point,” said Philomela, “the school’s defences have the problem more or less under control. Provided everyone is sensible, of course. Sometimes, people aren’t.”

And that brought them to 2003. The photographs were all in colour now, the records printed, not typed. Philomela said, “Here he is,” and took out a school photo, the traditional rows of children in smart jackets, names listed underneath. She pointed to the top corner. “Charles Green. This is a house photograph—he was in St Jude’s. Of course, he was also a School House boy. One of Chetwood’s traditional functions, as a school, is the education of young sorcerers.”

Walden looked at the photograph and said nothing.

Kenning peered at it. “Bad hair,” she said.

“Well, he was a teenager, you know,” said Philomela, but she laughed a little. “I’m afraid this one is a very typical story of schoolboy hubris. Green attempted to summon Old Faithful on purpose—heaven knows why. I believe he even talked some classmates into helping him. His was the only death, which was honestly very lucky, considering. Awful for him, of course.”

“Kids can be stupid,” said Kenning.

“They can, can’t they?”

Walden said nothing, and said nothing. She possibly should have said something. But it wasn’t Kenning’s business, or Philomela’s, not really. The purpose of this meeting was to give Chetwood’s Chief Marshal a clearer picture of the scale of what was lurking in the school’s magical shadow. It wasn’t to wake up old ghosts.

“Well, that’s completely fucking terrifying,” said Kenning as they walked through the colonnade and then cut across the quad for the staffroom door. It was ten o’clock and there was simply no way to avoid having a polite cup of tea with her, short of inventing a meeting or an urgent phone call. “There shouldn’t be a school here. You realise that, don’t you? There’s a demon the size of an elephant here, so there shouldn’t be a school.”

“Biomass is a tricky measure,” said Walden, “but I think a more accurate comparison would be whale, not elephant. One of the larger species of whale.”

Kenning gave her an exasperated look. “Not my point, Dr Walden.”