Thomas ran a hand through his thick hair. “If the demon were trapped and killed, what of those who are poisoned? Would they get better?”

James shook his head. “The sick will not be healed. We still need an antidote for that. But the demons will be gone, and that is quite a start.” He set the book down. “The Enclave has been searching for these demons with no success—how would they have guessed they were seeking the offspring of an extinct creature? But now that we know it is a Mandikhor…”

“In the stories of Merthykhuwar demons, they make their homes in between spaces,” Cordelia said slowly. “For instance, the border between two countries, or the middle of a bridge. Somewhere that is neither here nor there.”

James drew off his spectacles; he was biting his lip thoughtfully. “When I went into the shadow realm, from the ballroom,” he said, “I saw—among others things—Tower Bridge. A strange red light poured from it. I think—”

Matthew sat up straight. “We know Gast raised the demon from a bridge,” he said. “A place between, as Cordelia said. Perhaps it still resides there.”

“So if we were to go to Tower Bridge, with a Pyxis, it’s possible that we could recapture the Mandikhor?” said Lucie. “And then the Khora would disappear—just as if it had died?”

“Yes, but we’d have to get a Pyxis first,” said Christopher practically. “That would be difficult.”

“But perhaps not impossible,” said Matthew. He was tapping his fingers restlessly against the arm of his chair, his hair and necktie disheveled. “If most were destroyed after the Clockwork War…”

“A few remain,” said James. “Unfortunately, they’re in Idris.”

“I was afraid you were going to say that,” muttered Matthew, reaching for his flask again. “I think it will be noticed by the Clave if we disappear from London and turn up in Idris, rooting around the Gard like treasure hunters.”

James gave him an exasperated look. “The only Pyxides in the Clave’s possession are in Idris. There are a few others. We just need to find one. There’s a certain shop in Limehouse—”

“Wait,” said Cordelia suddenly. “A box covered in alchemical symbols—the ourobouros is an alchemical symbol, isn’t it? Matthew, didn’t we see a box with a serpent design on it? In the Hell Ruelle?”

Matthew started. “Yes,” he said. “In the chamber of Hypatia Vex. A wooden box with an ourobouros symbol burned into the sides. It makes sense; Hypatia is an inveterate collector.”

“Excellent,” said Christopher. “We’ll just tell her we need it, then.”

“Go ahead, if you fancy being turned into a china cabinet,” said James. “Hypatia does not like Shadowhunters.” He looked thoughtful. “Good catch, though, Daisy. There must be some way for us to get to it.”

“We could rob the Hell Ruelle,” said Thomas.

“And wear masks,” said Lucie eagerly. “Like highwaymen.”