The King must want the Black Volume very badly, to have brought his Riders into it. In old days, they had hunted giants and monsters. Now they were hunting the Blackthorns. Mark felt cold all over.

Mark could hear Magnus speaking in a low voice, also explaining the Seven: who they were and what they did. Alec had given Cristina a gray shirt that was probably Ty’s; she was holding it, a Tracking rune on the back of her hand, but she was shaking her head even as she clutched it tighter. “It isn’t working,” she said. “Maybe if Mark tries—give him something of Livvy’s—”

A black flounced dress was shoved into Mark’s hands. He couldn’t picture his sister wearing something like it, but he didn’t imagine that was the point. He held it tightly, sketching a clumsy Tracking rune onto the back of his right hand, trying to remember the way Shadowhunters did this—the way you blanked your mind, reached out into the nothingness, trying to find the spark of the person you sought at the other end of your own reaching imagination.

But there was nothing there. The dress felt like a dead thing to his touch. There was no Livvy in it. There was no Livvy anywhere.

He opened his eyes on a gasp. “I don’t think this is going to work.”

Magnus looked confused. “But—”

“Those are not their garments,” said Kieran, lifting his head. “Do you not recall? Clothes were lent to them when they arrived here. I heard them complaining of it.”

Mark wouldn’t have thought Kieran had been paying enough attention to what the Blackthorns had been saying to take note of such details. Apparently he had.

But that was the way of Hunters, wasn’t it? Seem as if you are paying no attention, but absorb every detail, Gwyn had often said. A Hunter’s life can depend on what he knows.

“Is there really nothing of theirs?” Magnus demanded, a slight edge of panic in his voice. “The clothes they were wearing when they got here—”

“Bridget threw them away,” said Cristina.

“Their steles—”

“They would have with them,” said Mark. “Other weapons would be borrowed.” His heart was hammering. “Isn’t there anything you can do?”

“What about Portaling to the Los Angeles Institute?” said Alec. “Grabbing some of their things from there—”

Magnus had begun to pace. “It’s barred from Portaling right now. Security concerns. I could look for a new spell, we could send someone to dismantle the block on the California Institute, but any of those things takes time—”

“There is no time,” said Kieran. He straightened up. “Let me go after the children,” he said. “I pledge my life I will do everything I can to find them.”

“No,” Mark said, rather savagely, and saw the stricken look that passed over Kieran’s face. There was no time to explain or clarify, though. “Diana—”

“Is in Idris and cannot help,” said Kieran. Mark had slipped his hand into his pocket. His fingers closed on something small, smooth, and cold.

“It might be time to summon the Silent Brothers,” said Magnus. “Whatever the consequences.”

Cristina winced. Mark knew she was thinking of Emma and Jules, of the Clave meeting in Idris, of the ruination and danger the Blackthorns faced. A ruination that would have taken place on Mark’s watch. Something that Julian would never have allowed to happen. Disasters did not happen on Jules’s watch—not ones he couldn’t fix.

But Mark couldn’t think of that. His whole mind, his heart, was filled with the image of his brother and sister in danger. And they were more than his brother and sister at that moment: He understood what Julian felt when he looked at them. These were his children, his responsibility, and he would die to save them.

Mark drew his hand out of his pocket. The gold acorn glittered in the air as he threw it. It struck the opposite wall and broke open.

Cristina whirled. “Mark, what are you—?”

There was no visible change in the library, but a scent filled the room, and for a moment it was as if they stood in a glade in Faerie—Mark could smell fresh air, dirt and leaves, earth and flowers, copper-tinged water.

Kieran had tensed all over, eyes full of a mixture of hope and fear.

“Alec,” Magnus said, reaching out a hand, and his voice was less a warning than a sort of stripped-down urgency—the uncanniness of Faerie had come into the room, and Magnus was moving to protect what he loved. Alec didn’t move, though, only watched with steady blue eyes as a shadow rose against the far wall. A shadow with nothing to cast it.

It stretched upward. The shadow of a man, head bent, broad shoulders slumped. Cristina put her hand to the pendant at her throat and murmured something—a prayer, Mark guessed.

The light in the room increased. The shadow was no longer a shadow. It had taken on color and form and was Gwyn ap Nudd, arms crossed over his thick chest, two-colored eyes gleaming from beneath heavy brows. “Mark Blackthorn,” he said, his voice a rumble. “I did not give that token to you, nor was it meant for you to use.”

“Are you really here?” Mark demanded, fascinated. Gwyn seemed solid enough, but if Mark looked closely, he thought he could see the edges of the window frames through Gwyn’s body . . . .

“He’s a Projection,” said Magnus. “Greetings, Gwyn ap Nudd, escort of the grave, father of the slain.” He bowed very slightly.

“Magnus Bane,” said Gwyn. “It has been a long time.”

Alec kicked Magnus in the ankle—probably, Mark suspected, to keep Magnus from saying something about how it hadn’t been long enough.

“I need you, Gwyn,” said Mark. “We need you.”

Gwyn looked disgruntled. “If I had wanted you to be able to call on me at your will, I would have given the acorn to you.”

“You called on me,” Mark said. “You came to me to ask me to help Kieran, and so I rescued him from the Unseelie King, and now the Riders of Mannan are hunting my brothers and sisters, who are only children.”

“I have carried the bodies of countless children from the battlefield,” said Gwyn.

He did not mean to be cruel, Mark knew. Gwyn simply had his own reality, of blood and death and war. There was never a time of peace for Gwyn or the Wild Hunt: Somewhere in the world, there was always war, and it was their duty to serve it.

“If you do not help,” said Mark, “then you make yourself a servant of the Unseelie King, protecting his interests, his plans.”

“Is that your gambit?” Gwyn said softly.

“It’s no gambit,” said Kieran. “The King my father means to wage a war; if you do not move to position yourself against him, he will presume you are with him.”

“The Hunt stands with no one,” said Gwyn.

“And that’s precisely who will believe that is true, if you do not act now,” said Mark. “No one.”

“The Hunt can find Livvy and Ty and Kit,” said Cristina. “You are the greatest seekers the world has ever known, much greater than the Seven Riders.”

Gwyn gave her a slightly incredulous look, almost as if he couldn’t believe she’d spoken at all. He looked half-amused, half-exasperated by her flattery. Kieran, on the other hand, looked impressed.

“Very well,” Gwyn said. “I will attempt it. I promise nothing,” he added darkly, and vanished.

Mark stood staring at the place Gwyn had vanished from, the blank wall of the library, unmarked by shadows.

Cristina offered him a worried smile. Cristina was always a revelation, he thought. Gentle and honest, but astonishingly capable of plying faerie tricks if necessary. Her words to Gwyn had sounded utterly sincere.

“He might sound reluctant, but if Gwyn says he will attempt something, he will leave no stone unturned,” Magnus said. He looked absolutely exhausted in a way Mark didn’t remember ever having seen him look before. Exhausted, and grim. “I’m going to need your help, Alec,” he said. “It’s time for me to Portal to Cornwall. We need to find Emma and Julian before the Riders do.”

*