“Do you think I have nothing to contribute to a fight?” Ty had asked.

“No,” Julian had said, and meant it. “But you’re hurt, and I—”

“It’s a fight. We might all get hurt.” Ty had looked directly into Julian’s eyes. He could tell that Ty was doing it for him, because he remembered that Julian had told him that people often looked directly into each other’s eyes to show that they were telling the truth. “I want to go. I want to be there to help Tavvy, and I want you to let me. It’s what I want, and that should matter.”

Ty was in the weapons room with them now. It was a cavernous space with no windows. Every spare inch of the walls was hung with swords, axes, and maces. Gear, belts, and boots were stacked in piles. There was a ceramic tile bowl full of steles, and a table covered with a long cloth held seraph blades.

Julian could sense them all around him, his friends and family. He knew Mark was at his side, toeing off his shoes and kicking his feet into boots. He knew Emma was at the counter, lining up seraph blades that had already been named and prepared, sliding some into her belt and distributing the rest. His awareness of her swung as she moved around the room like the needle on a compass.

Above all, though, he was aware of Tavvy, out there somewhere, needing him. There was a cold terror in him that threatened to pull the determination out of his bones and sap his concentration. Pushing it away to focus on what was happening here and now was one of the hardest things he’d ever done. He bitterly wished that things were different, that they had the cooperation of the Clave, that they could have gotten to Magnus and asked for a Portal.

But it was no use wishing.

“Talk,” he snapped at Kieran, pulling down a weapons belt from a shelf. “That black light, you said it was ‘faerie magic.’ Did you mean dark magic?”

Now that Mark was no longer looking directly at him, Kieran seemed bored and annoyed. He leaned against the central table, taking care not to come in contact with any of the weapons—not, his expression made clear, because they were sharp or frightening but because they were Nephilim weapons and therefore repellent.

“The question is whether it will show up on the Clave’s map,” said Ty, buckling on protective gauntlets. He was already in his gear, and the slight outline of the bandage on his calf was barely visible under the thick fabric. “The one Magnus uses to track dark magic use. Or is that blocked like the cell phones?”

“It was Unseelie magic, but not dark in nature,” said Kieran. “It will not show itself on the map. They were very sure of that.”

Julian frowned. “Who is they? In fact, how do you know so much about Malcolm?”

“Because of Iarlath,” said Kieran.

Mark turned to stare. “Iarlath? What has he to do with this?”

“I thought you knew that at least,” Kieran muttered. “Iarlath and Malcolm have been in this together since the attack on the Institute five years ago.”

“They’re allies?” Mark demanded. “How long have you known?”

“Only a short time,” said Kieran. “I became suspicious when Iarlath so strongly refused to allow you to come back to Faerie. He wished you to stay here, so much so that he staged that charade of punishment with the whipping so that you would not return with us. After that I realized there was more to the plan of having you here at the Institute than finding the murderer who had taken faerie lives. It was about preventing anyone in your family from being able to go to the Clave until it was too late.”

Emma had a seraph blade in each hand and Cortana on her back; she had paused, her face stiff with shock. “Iarlath said something to me when he was—when he was whipping me,” she said. “That Shadowhunters don’t know who to trust. He meant Malcolm, didn’t he?”

“Most likely,” said Kieran. “Malcolm’s is the shadow hand that has guided the Followers, and Malcolm killed your parents five years ago.”

“Why?” Emma was rigid. Julian wanted to go to her so badly it hurt. “Why did he kill my parents?”

“As I understand it?” Kieran said, and there was a tinge of pity to his voice. “It was an experiment. To see if the spell worked.”

Emma stood speechless. Julian asked it for her, the question she couldn’t voice. “What do you mean, an experiment?”

“Years ago, Iarlath was one of the Fair Folk who allied themselves with Sebastian Morgenstern,” said Kieran. “He was also a friend to Malcolm. As you probably know, there are certain books warlocks are forbidden to own, but which can be found in some Shadowhunter libraries. Necromantic tomes and the like. One of those is the Black Volume of the Dead.”

“The one that the poem talked about,” said Dru. Though her face was still tearstained, she had put on her gear and was braiding her hair carefully back from her face. It hurt Julian’s heart, to see her like that. “‘Find the black book at any cost.’”

“There are many black books,” said Kieran. “But this was one Malcolm specifically wanted. Once the Institute was cleared of Shadowhunters and Sebastian departed, Malcolm took the opportunity to slip in and steal the book from the library. After all, when else was the Institute going to be unguarded, the door open? He took it, and he found the spell he wanted, and he saw that it required the sacrifice of Shadowhunter life. That was when your parents returned to the Institute, Emma.”