“Did the demons vanish suddenly, the same way they did at the lake?”

“Apparently the Baybrooks said they were gone nearly as quickly as they appeared.”

“It seems to me,” said Cordelia, “that they are not simply seeking to kill. They seek to bite. To sicken.”

James frowned. “But Randolph was killed.”

“He was the only one fighting back,” said Cordelia. “It seems to me they are willing to kill—Barbara or Piers could easily have died of blood loss—but their directive is to spread this—this infection.”

“So you think someone is controlling them,” said James. “Good. So do I. Hopefully we can find out who from Gast.”

“Gast?” echoed Cordelia.

His eyes sparked a dark gold. “One good thing happened last night. It seems your trip to the Hell Ruelle was successful. Hypatia Vex sent Ragnor Fell to assist us with the name of a warlock who may have summoned these demons. Emmanuel Gast.” He glanced up toward the windows of her house. “Ragnor did insist that we keep the information a secret.”

“Another secret,” said Cordelia. “There do seem to be so many now. And poor Thomas—does he know—?”

“About Gast? Yes. Ragnor came just before we found out about Barbara.” Pain flashed across James’s face. “Thomas blames himself for her death, though there is nothing he could have done.”

James looked exhausted, Cordelia realized. He had come far out of his way to tell her this news, so that she did not have to hear it from people who didn’t know Thomas or care about him or his friends.

He must be desperate to leave, she thought. She couldn’t keep him here talking when he no doubt wished to be with his family, or with Grace.

“It was kind of you to come and tell me,” she said, leaning against the doorway. “I would ask you in for tea, but I know you must be eager to return to your family.”

“Actually, I am not returning to the Institute. I have made a plan with Matthew and Lucie to confront Gast in his flat. I’ll be meeting them there. I came to see if you would join us.”

Surprised, Cordelia said, “Oh, did Lucie ask you to fetch me along?”

James hesitated. “Yes. She did.”

“Anything for my future parabatai, of course,” Cordelia said. And she did mean it. She wanted badly to see Lucie, and even more to have something useful to do. Some way to help. All night she had been thinking of Barbara, who she had known so little, but who had been so young, and seemed so kind.

“I doubt this warlock will be happy to see us,” said James. “Bring your gear and Cortana; we must be ready to fight.”

* * *

Emmanuel Gast lived in a flat above a handkerchief manufacturer’s, near the junction between Cheapside and Friday Street. Matthew pointed up Friday Street as they went past. “There used to be a pub up that street called the Mermaid Tavern, where Shakespeare used to drink.”

In Lucie’s opinion as a writer, this was not an artistically inspiring avenue. On each side of the street were dingy brown buildings with narrow leaded windows and grubby Dutch gables. Awnings hanging outside several buildings were dyed a mottled brown too, not by design but with the dust of the streets and the smog of the city. Cheapside was one of the busiest thoroughfares in London, crowds surging from the fishmongers’ stalls all the way to the white bell tower of St. Mary-le-Bow.

She wrinkled her nose. “I don’t think much of Shakespeare’s taste.”

Matthew smiled, though he looked as tired as Lucie felt. He wore dark gear just as she did, a white mourning band around his wrist and a white flower in his buttonhole. He had been making jokes all morning, and Lucie had been trying as best she could to keep up. It was hard not to let her mind wander to thoughts of Barbara, of the now even more crowded infirmary at the Institute. Of when the next attack might come, and who might be hurt or killed in it.

“Luce.” Matthew touched her arm lightly. They were glamoured, and the crowds moved around them, parting like a river forking around a central island. Newsboys hawking the Evening Standard darted up and down the streets: Matthew had greeted one earlier, explaining to Lucie that he was an Irregular, one of the many Downworlder street urchins who ran errands out of the Devil Tavern. “There is something rather odd I wanted to talk to you about. Charles—well, Charles is always odd, but Charles and Grace—”

“James! Cordelia!” Lucie rose up on her toes, waving through the crowds. Her brother and Cordelia had alighted from their carriage some distance away and were walking toward them. They were clearly deep in conversation, their heads bent together as if they were exchanging secrets.

Lucie sank back down on her heels, a little puzzled. She rarely saw James lost in conversation with anyone other than his three closest friends.

“Interesting,” said Matthew, his green eyes narrowed. He raised a hand and waved, and this time James saw them. He and Cordelia darted through the crowds to catch them at the corner. Lucie stared a little: Cordelia looked so very different out of the awful clothes her mother made her wear. She was in gear: a long tunic over boots and trousers, her red hair caught back in a braid, and a leather satchel over one shoulder. She looked even younger and prettier than she had at the Institute ball.

“It’s a boardinghouse,” said Matthew as soon as Cordelia and James were within earshot. “We’ve already been inside. The landlady said our friend Emmanuel Gast was ‘away from home for an indefinite period.’  ”

“Matthew was unable to charm her,” said Lucie. “The woman is a block of concrete in human form. We did manage to find out the flat’s the one on the third floor, though.”

A smile crept over James’s face. One of the things he enjoyed most about patrolling was clambering around rooftops. “Then we go up the side of the building.”

“I was afraid of this,” Matthew muttered as they followed James into a narrow, rubbish-choked alley. “My boots are new.”

“Stiffen your sinews, Matthew,” said James. “And cry God for Harry, England, and Saint George!”

“Shakespeare,” said Cordelia. “Henry V.”

“Well spotted,” said James, and produced a grappling hook. He threaded the end of a rope through and stood back to throw it. His aim, as always, was excellent: the grappling hook sank into the lintel of a third-floor window; the rope unfurled down the side of the building. “Once more unto the breach,” he announced, and began to climb.

James was followed up the rope by Cordelia, then Lucie, and Matthew last, still cursing the dirt on his boots. Lucie was halfway to the window when she heard a yell. Glancing down, she saw that Matthew was on his hands and knees in the alley. He must have fallen from the rope.

“Are you all right?” she asked in a loud whisper.

When he stood up, his hands were shaking. He deliberately avoided Lucie’s gaze as he caught at the rope. “I told you,” he said. “New boots.”

Lucie began to climb the rope again. James had reached the window: balanced on the lintel, he glanced around and kicked the window in; the whole thing collapsed inward, sash, glass, and all. He vanished inside, followed by Cordelia. Lucie and Matthew climbed in after them.

The flat was dim and filled with a stench as of rotting waste. There was brown wallpaper, smeared with grease. Pictures torn from magazines were stuck to the walls. There was very little light, though Lucie could see a humped old sofa and a stained Turkish rug. A tall bookshelf was lined with shabby-looking tomes; James eyed them curiously.

“I think Ragnor was right,” he said. “There’s a real concentration on the study of dimensional magic here.”

“No stealing the books and bringing them back to the Devil Tavern,” said Matthew. “It would not be the first time your book kleptomania has gotten us in trouble.”

James held his hands up innocently and went to search beneath some of the furniture. Cordelia followed his lead and peeked behind the cheap wooden frame of a small oil painting showing Queen Elizabeth, all scarlet hair and white powder, making a most unpleasant face.

“Look at these.” There was dust in James’s hair, and he was frowning. “I wonder if they’re some kind of weapon?”

He indicated what looked like a heap of broken pieces of wood, scattered over the floor behind the sofa. “They’re awfully dusty,” said Cordelia. “As if no one’s touched them in ages.”

James bent to pick one up, frowning, just as Matthew glanced over. He’d been searching a small, shabby desk covered with loose papers. He held up a messy sketch. “James, look here.”

James squinted. “It’s a box. Surrounded by scrawls.”

“It’s not a box,” Matthew told him helpfully. “It’s a drawing of a box.”

“Thank you, Matthew,” James said dryly. He tilted his head to the side. “There’s something familiar about it.”

“Does it remind you of boxes you have been acquainted with before?” said Matthew. “Look at the scrawls a bit more closely. Don’t they remind you of runes?”

James took the paper from his parabatai. “Yes,” he said, sounding a bit surprised, “very much so—not runes that we use, but still awfully close—”

Cordelia, who had knelt down to look at the shards of wood, said, “These do have runes carved into them—our kind of runes—but they also look as if they’ve been part-eaten by a sort of acid.”

“And look at those scratches on the wood,” said James, joining her. He glanced at Gast’s sketch, and then back at the shards. “It’s as if—”

Lucie half heard Matthew say something in response, but she was already taking advantage of their distraction to slip through a half-open door into the flat’s small bedroom.

Her hand flew to her mouth. She gagged and bit down hard on her own thumb, the pain cutting through the nausea like a knife.