“Lucie,” James said. “I don’t blame them or expect they forgot. But this is Belial. He’s a Prince of Hell. Half my life, he’s reached into my waking dreams. If anyone could break through the protection spell, a Prince of Hell—”

“It should protect against any demonic interference,” said Christopher. “The spell was originally intended to keep Lilith away specifically. The angels Sanvi, Sansanvi, and Semangelaf are her mortal enemies. But the full ritual, performed by the Silent Brothers, should be strong enough to keep away even Belial, or Leviathan.”

“An excellent reminder it could be worse,” said James. “Our grandfather could have been Leviathan. We’d both have tentacles.”

“So hard to find clothes that would fit,” said Christopher sympathetically.

“So what do these sigils do?” wondered Thomas, settling back into his chair. “Do they just serve as elaborate signatures?”

James set the book down on the inlaid table by the fire. “They are more than symbols. They can be used in summoning. Ancient cults used to create massive sigils with standing stones or marks on the ground, which would serve as gateways for demons.” He paused, arrested by a sudden thought. “Christopher, do you have a map of London?”

“I am a scientist,” said Christopher, “not a geographer! I don’t have a map of London. I do have a beaker of Raum venom,” he added, “but it’s in my shoe, and will be difficult to reach.”

“Does anyone have questions about that?” James said, glancing around. “No? Good. All right, a map—”

Anna clambered lightly onto an upholstered chair and reached for a high shelf of books. She drew down a volume of maps. “How fortunate that you have a well-stocked library, James.”

James took the book and set it down on the table, flipping through the pages. The map of London was easy to find: no Londoner did not know the shape of his city, with its crowded banks, its bridges, its river winding past wharves and docks.

Over Thomas’s protests, James flicked a pen from his friend’s pocket. He began to mark spots on the map, counting them off in order. “Clerkenwell, Fitch Lane, Shoe Lane, Shepherd Market—”

“I think he is possessed,” said Thomas. “He’s defacing a book.”

“Desperate times call for desperate measures.” James squinted. Splashed across the map were his marks, one for each address where a body had been found. He had connected them with his pen, but they formed nothing resembling Belial’s sigil. “I had wondered—”

“If someone was trying to draw the sigil, so to speak, with the locations chosen for the murders,” said Christopher, his face alight with thought. “I realized what you were doing—it’s very clever, but I don’t see how that could even be the beginning of Belial’s sigil. It’s all circles, and this is more like a line that hooks at the end—”