Walden did notice, as they moved, that the lesser demons she’d spotted on her way up to the tower had all disappeared. Had they fled, or had they been consumed? Neither possibility was comforting.

She stifled a sigh of relief when they reached the disappeared Victorian office where she’d met Merringham’s ghost. No sign of him now, but the thread of magic tied to her brooch led straight through the wall. Not far now. Nikki and Mathias were both very quiet, but they had started to look less scared. Walden touched the wall and it shimmered. “Walk straight through,” she said. “Imagine it’s not there, and it won’t be.”

They walked through the wall. It disintegrated, revealing School House’s airy present-day kitchen on the other side. Walden put her arm out abruptly. Mathias walked into it. She did not glance over at him. She did not dare look away.

Her owl brooch was no longer jammed into anything. The thread of Walden’s magic looped through it jiggled and twisted as the figure sitting on the table tossed it from hand to hand. Left, then right. Left, then right. He set it on one end on the kitchen table and gave it a spin. The enamelled owl clattered away and fell onto the stone flags.

The figure looked up at them and grinned. He had slightly wonky canine teeth. His jeans were threadbare. Demonic power hung around him in a malevolent cloud.

“Hey, Saffy, you made it,” said Old Faithful, in the voice of a boy who had been dead for twenty years. “I was starting to get worried.”

chapter nine CHARLIE

Walden looked at the boy in the threadbare jeans and said nothing.

“You got good! Like, really good! Congrats on the doctorate. Fancy.”

She took a breath, and raised one hand, and spoke the opening syllables of the strongest banishment she knew. Her hand was shaking. She tried to force it steady.

“Oh, come on,” said Old Faithful, unbothered, smiling. “Don’t waste your time. You can get out from here. I won’t pick a fight. But you’re not getting both of them past me. You know it, I know it. Which one are you leaving behind?”

“Neither,” said Walden.

“Why not?” said the demon. “You left me behind.”

“Dr Walden?” said Nikki.

“Don’t listen to anything it says,” said Walden.

“Yeah, you’ve done enough, Niks, haven’t you,” said Old Faithful. It put on a sonorous tone. “I had your mother and father, girl, I licked your brother’s little bones clean, and if you desire vengeance then you know what you must do— Ha, can’t believe you fell for that! You must be pretty thick, huh? Or maybe you’ve just got a shit teacher.”

“Don’t listen,” said Walden.