Clary felt a surge of hope mixed with terror; she forced herself to remain silent, but saw Amatis’s eyes flick toward her. She didn’t seem surprised to see Clary on the throne: on the contrary, her lips curved into a smirk. “Would you like me to set the rest of the army to searching for them?” she said to Sebastian.

“There’s no need.” He glanced up toward Clary and smiled; there was a sudden explosive shattering sound, and the window behind her, the one that had looked out on Alicante, splintered into a spiderweb of mazed lines. “The borders are closing,” Sebastian said. “I will bring them to me.”

“The walls are closing in,” Magnus said.

Alec tried to pull Magnus farther upright; the warlock slumped heavily against him, his head almost on Alec’s shoulder. Alec had absolutely no idea where they were going—he had lost track of the twisting corridors what felt like ages ago, but he had no desire to communicate that to Magnus. Magnus seemed to be doing badly enough as it was—his breathing ragged and shallow, his heartbeat rapid. And now this.

“Everything’s fine,” Alec soothed, his arm sliding around Magnus’s waist. “We just have to make it to—”

“Alec,” Magnus said again, his voice surprisingly firm. “I am not hallucinating. The walls are moving.”

Alec stared—and felt a flutter of panic. The corridor was heavy with dusty air; the walls seemed to shimmer and tremble. The floor warped as the walls began to slide toward each other, the corridor narrowing from one end like a trash compactor slamming closed. Magnus slipped and hit one of the buckling walls with a hiss of pain. Panicked, Alec seized his arm and pulled Magnus toward him.

“Sebastian,” Magnus gasped as Alec began to drag him down the hall, away from the collapsing stone. “He’s doing this.”

Alec managed an incredulous look. “How would that even be possible? He doesn’t control everything!”

“He could—if he sealed the borders between the dimensions.” Magnus took a rattling breath as he pushed himself into a run. “He could control this whole world.”

Isabelle shrieked as the ground opened up behind her; she threw herself forward just in time to avoid toppling into the chasm that was splitting the corridor apart. “Isabelle!” Simon shouted, and reached to catch her by the shoulders.

He forgot, sometimes, the strength that his vampire blood flooded through his body. He wrenched Isabelle up with such force that they both toppled backward and Izzy landed on top of him. Under other circumstances, he might have enjoyed it, but not with the stone keep shuddering itself apart around them.

Isabelle sprang to her feet, pulling him up after. They had lost Luke and Jocelyn back in one of the other corridors as a wall had split apart, shedding mortarless rocks like scales. Everything since then had been a mad dash, dodging splintering wood and falling stones, and now chasms opening up in the ground. Simon was fighting despair—he couldn’t help but feel that this was the end; the fortress would fall apart around them, and they would die and be buried here.

“Don’t,” Isabelle said, breathless. Her dark hair was full of dust, her face bloody where flying rock had cut her skin.

“Don’t what?” The ground heaved, and Simon half-ducked, half-fell forward into another corridor. He couldn’t rid himself of the thought that somehow the fortress was herding them. There seemed a purpose to its dissolution, as if it were directing them somehow. . . .

“Don’t give up,” she gasped, flinging herself against a set of doors as the corridor behind them began to crumble; the doors swung open, and she and Simon tumbled into the next room.

Isabelle sucked in a gasp, quickly cut off as the doors slammed behind them, shutting away the explosive noise of the keep. For a moment Simon simply thanked God that the ground under his feet was steady and the walls weren’t moving.

Then he registered where he was, and his relief vanished. They were in an enormous room, semicircular in shape, with a raised platform at the curved end half cast in shadow. The walls were lined with Endarkened warriors in red gear, like a row of scarlet teeth.

The room stank like pitch and fire, sulfur and the unmistakable taint of demon blood. The body of a bloated demon lay sprawled against one wall, and near it was another body. Simon felt his mouth go dry. Jace.

Within a circle of glowing runes etched on the floor stood Sebastian. He grinned as Isabelle gave a cry, ran to Jace, and dropped down by his side. She put her fingers to his throat; Simon saw her shoulders relax.

“He’s alive,” Sebastian said, sounding bored. “Queen’s orders.”

Isabelle looked up. Some of the strands of her dark hair were stuck to her face with blood. She looked fierce, and beautiful. “The Seelie Queen? When has she ever cared about Jace?”

Sebastian laughed. He seemed to be in an enormously good mood. “Not the Seelie Queen,” he said. “The queen of this realm. You may know her.”

With a flourish he gestured toward the platform at the far end of the room, and Simon felt his unbeating heart contract. He had barely glanced at the dais when he had come into the room. He saw now that on it were two thrones, of ivory bone and melted gold, and on the right-hand throne sat Clary.

Her red hair was incredibly vivid against the white and gold, like a banner of fire. Her face was pale and still, expressionless.

Simon took an involuntary step forward—and was immediately blocked by a dozen Endarkened warriors, Amatis at their center. She carried a massive spear and wore an expression of frightening venom. “Stop where you are, vampire,” she said. “You will not approach the lady of this realm.”

Simon staggered back; he could see Isabelle staring incredulously from Clary, to Sebastian, to him. “Clary!” he called; she didn’t flinch or move, but Sebastian’s face darkened like a thunderstorm.

“You will not say my sister’s name,” he hissed. “You thought she belonged to you; she belongs to me now, and I will not share.”

“You’re insane,” Simon said.

“And you’re dead,” Sebastian said. “Does any of it matter now?” His eyes raked up and down Simon. “Dear sister,” he said, pitching his voice loudly enough for the whole room to hear it. “Are you absolutely sure you want to keep this one intact?”

Before she could answer, the entryway to the room burst open and Magnus and Alec spilled in, followed by Luke and Jocelyn. The doors slammed behind them, and Sebastian clapped his hands together. One hand was bloody, and a drop of blood fell at his feet, and sizzled where it hit the glowing runes, like water sizzling on a hot skillet.

“Now everyone’s here,” he declared, his voice delighted. “It’s a party!”

In Clary’s life she had seen many things that were wonderful and beautiful, and many things that were terrible. But none were as terrible as the look on her mother’s face as Jocelyn stared at her daughter, seated on the throne beside Sebastian’s.

“Mom,” Clary breathed, so softly that no one could hear her. They were all staring at her—Magnus and Alec, Luke and her mother, Simon and Isabelle, who had moved to hold Jace in her lap, her dark hair falling down over him like the fringe of a shawl. It was every bit as bad as Clary had imagined it would be. Worse. She had expected shock and horror; she hadn’t thought of hurt and betrayal. Her mother staggered back; Luke’s arms went around her, to hold her up, but his gaze was on Clary, and he looked as if he were staring at a stranger.