I belong here, Saffy, its voice whispered in Walden’s thoughts, clear and coherent and terribly familiar. She had worked at Chetwood for three years and not seen a flicker of this thing; but it had been here all along, and it knew who she was. I still belong. You know me. You know I do.

And then it was dislodged. Something shook it loose from the summoning array and suddenly the full force of Walden and Kenning together was enough to send it whirling away into the void. Walden’s chest heaved as she panted. There was sweat dripping down the back of her neck. She was almost surprised to see the white walls of the arcane lab come back into focus. The black and yellow paint of the incursion wards had all turned scarlet. Kenning, still standing in the remnants of the now inert pentagram, collapsed into a crouch and gasped for breath. “How did you do that?” she demanded.

“That wasn’t me,” Walden said. She turned to the teacher’s desk.

Nikki was standing there, wide-eyed with fright. Aneeta, Will and Mathias were clustered behind her. Nikki held in her shaking hand the risk assessment form that Walden put down on the desk at the start of every lesson.

There was a colourful box at the bottom of the page with a quick banishment cantrip. It was, intentionally, the sort of spell that it was easy to cast in a hurry in an emergency. Walden had felt it slide under the demon’s grip on the summoning array and pry it loose.

“Quick thinking, Nikki,” she said. She felt a certain measure of smugness. Laura Kenning and her narrow Marshal assessment could not have been more wrong about Nicola Conway. “Well done. Have a house point.”

In justice, after a narrow miss like that, Walden would have had a sit-down and a nice cup of tea. Unfortunately, there was still half an hour of the double left. She drank the last of her cold coffee instead, and regretted it immediately. “All right, let’s review,” she said. “I’m sure you’ve already guessed that your homework is to write up a report on today’s practical. What have we learned?”

A painful silence. Kenning had taken up her stance in the corner again. She looked tired.

“Was that him?” said Will. “Old Faithful?”

Of course; Will had a long family connection to Chetwood, he would have heard of the school’s largest and most alarming demonic pest if anyone had. “It was a very large demon, yes,” said Walden. “Precise identification would be difficult without summoning it. Should we summon it?”

“No,” said Aneeta immediately.

Good. “Why not?”

“Um, because it would kill us?”

“Correct,” Walden said.

“Did anyone else, like—hear it?” said Aneeta. “It said—”

She stopped.