She’d had to get out of bed in the middle of the night to fix them three times in the three years she had worked here. It didn’t sound like much, unless you understood what was at stake. The whole system ought to have been shut down and rebuilt from scratch to modern standards, but to do that would take about five years, and those would be five expensive years in which no fees came in. Chetwood School would not survive. Instead, like most schools, the institution went on from year to year by doing what had always more or less worked, or at least seemed to work, or at any rate kept things going.

So Walden’s days were filled, and she barely got to teach. Which was sad, because she loved to teach. She did, at least, do the Year Seven arcane safety course, on the teaching carousel with Relationships Ed, debating, Mindfulness in Schools, and beginners’ yoga. It gave her three weeks with each class, just enough time to learn all their names. Her sixth formers—Years Twelve and Thirteen—were the only sets she saw all the way through; four times a week, for two hours at a time, for two years.

It was unusual for a deputy head to take on an A-level examination set, but invocation, Walden’s subject specialism, was hard to hire for. Modern academic magic was divided into three disciplines. Evocation was what most people thought about when they imagined someone doing magic: magicians using their own physical strength, speaking words and making gestures, to cast spells with immediate results. Instantiation was a more recent academic term for what had once been called alchemy, the branch of magic that used the physical fabric of the world to create long-lasting magical effects, like the warding produced by the thaumic engines.

Invocation was the discipline of the demon summoners.

Anyone from the Evocation or Instantiation Departments could teach the basics, just as Walden could have taught Year Eight Magic without any difficulty. Magical fundamentals were the same across all the arcane disciplines. But a magical A-level was a demanding academic course, and needed a confident teacher. Chetwood continued to advertise, and Walden regularly sent out feelers through her old academic supervisors and colleagues, hoping for a talented postgraduate. In the meantime, she would rather sacrifice her sleep and Sundays to work than have sixth formers taught demonic invocation by someone whose skills were not up to scratch.

It was October now of her fourth term with this set, and she felt she knew them rather better than she knew her own family, most of whom she hadn’t spoken to since last Christmas.

Take them in order: