Through the open window of her bedroom, she could see the demon towers, flashing gold and red. The colors of war.

She staggered to her feet, reaching for her gear, which was on a peg by the bed. She had just slid into it and was bending down to tie up her boots when the door to her room burst open. It was Julian. He skidded halfway inside before catching himself. He stared at the papers on the floor, and then at her. “Emma—didn’t you hear the announcement?”

“I was napping.” She clipped out the words as she attached the harness that held Cortana to her back, then slipped the blade into the scabbard.

“The city’s under attack,” he said. “We have to get to the Accords Hall. They’re going to lock us inside—all the kids—it’s the safest place in the city.”

“I won’t go,” Emma said.

Julian stared at her. He was wearing jeans and a gear jacket and sneakers; there was a shortsword stuck through his belt. His soft brown curls were wild and unbrushed. “What do you mean?”

“I don’t want to hide in the Accords Hall. I want to fight.”

Jules pushed his hands through his tangled hair. “If you fight, I fight,” he said. “And that means nobody carries Tavvy to the Accords Hall, and nobody protects Livvy or Ty or Dru.”

“What about Helen and Aline?” Emma demanded. “The Penhallows—”

“Helen’s waiting for us. All the Penhallows are up at the Gard, Aline included. There’s no one home but Helen and us,” said Julian, holding out a hand for Emma. “Helen can’t protect us all on her own and carry the baby, too; she’s only one person.” He looked at her, and she could see the fear in his eyes, the fear he was usually so careful to shield from the younger children.

“Emma,” he said. “You’re the best, the best fighter of all of us. You’re not just my friend, and I’m not just their older brother. I’m their father, or the closest thing to it, and they need me, and I need you.” The hand he was holding out was shaking. His sea-colored eyes were huge in his pale face: He didn’t look like anyone’s father. “Please, Emma.”

Slowly Emma reached out and took his hand, wrapping her fingers around his. She saw him let out a minute breath of relief, and felt her chest tighten. Behind him, through the open door, she could glimpse them: Tavvy and Dru, Livia and Tiberius. Her responsibility. “Let’s go,” she said.

At the top of the stairs Jace released Clary’s hand. She clutched at the balustrade, trying not to cough, though her lungs felt like they wanted to tear their way out of her chest. He looked at her—What’s wrong?—but then he stiffened. Audible behind them was the sound of racing feet. The Endarkened were on their heels.

“Come on,” Jace said, and started to run again.

Clary forced herself after him. Jace seemed to know where he was going, unerringly; she supposed he was using the map of the Gard in Alicante that he had in his head, burrowing in toward the center of the keep.

They turned into a long corridor; halfway down it Jace stopped in front of a set of metal doors. They were slashed with unfamiliar runes. Clary would have expected death runes, something that spoke of Hell and darkness, but these were runes of grieving and sorrow for a world destroyed. Who had etched them here, she wondered, and in what excess of mourning? She had seen runes of grief before. Shadowhunters wore them like badges when someone they loved had died, though they did nothing to ease suffering. But there was a difference between grief for a person and grief for a world.

Jace ducked his head, kissed her hard and fast on the mouth. “Are you ready?”

She nodded, and he swung the door open and stepped inside. She followed.

The room beyond was as large as the Council room in Alicante’s Gard, if not larger. The ceiling rose high above them, though instead of rows of seats a wide bare marble floor stretched toward a dais at the end of the room. Behind the dais were two massive, separate windows. Sunset light poured through each of them, though one sunset was the color of gold, and the other was the color of blood.

In the bloody golden light Sebastian knelt in the center of the room. He was etching runes into the floor, a circle of dark connected sigils. Realizing what he was doing, Clary started toward him—and then lurched back with a scream as a massive gray shape loomed up in front of her.

It looked like an enormous maggot, the only gap in its slick gray body its mouth full of jagged teeth. Clary recognized it. She’d seen one before in Alicante, rolling its slippery body over a pile of blood and glass and icing sugar. A Behemoth demon.

She reached for her dagger, but Jace was already leaping, sword in hand. He flew through the air and landed on the back of the demon, stabbing down through its eyeless head. Clary backed away as the Behemoth demon thrashed, spraying stinging ichor, a loud, ululating wail coming from its open throat. Jace clung to its back, ichor spraying up over him as he brought the sword down, and down, and down again until the demon, with a gurgling scream, collapsed to the ground with a thud. Jace rode it down, knees clamped to its sides, until the last moment. He rolled off and hit the ground standing.

For a moment there was silence. Jace looked around the room as if he expected another demon to lunge out at them from the shadows, but there was nothing, only Sebastian, who had risen to his feet in the center of his now completed circle of runes.

He began to clap slowly. “Lovely work,” he said. “Really excellent demon-dispatching. I bet Dad would have given you a gold star. Now. Shall we dispense with the pleasantries? You recognize where we are, don’t you?”

Jace’s eyes moved around the room, and Clary followed his gaze. The light outside the windows had dimmed slightly, and she could see the dais more clearly. On it sat two immense—well, the only word for them was “thrones.” They were ivory and gold, with gold steps leading up to them. Each had a curved back embossed with a single key.

“‘I am he that liveth, and was dead,’ ” said Sebastian, “ ‘and behold, I am alive for evermore, and have the keys of hell and of death.’ ” He made a sweeping gesture toward the two chairs, and Clary realized with a sudden jolt that there was someone kneeling beside the left-most chair—a Dark Shadowhunter in red gear. A woman on her knees, her hands clasped in front of her. “These are the keys, made over in the shapes of thrones and given to me by the demons who rule this world, Lilith and Asmodeus.”

His dark eyes moved to Clary, and she felt his gaze like cold fingers walking up her spine. “I don’t know why you’re showing me this,” she said. “What do you expect? Admiration? You won’t get it. You can threaten me if you want; you know I don’t care. You can’t threaten Jace—he has the fire of Heaven in his veins; you can’t hurt him.”

“Can’t I?” he said. “Who knows how much of Heaven’s fire he has still in his veins, after that fireworks display he put on the other night? That demon got to you, didn’t she, brother? I knew you could never quite bear the knowledge of it, that you had killed your own kind.”

“You forced me to murder,” Jace said. “It wasn’t my hand holding the knife that killed Sister Magdalena; it was yours.”

“If you like.” Sebastian’s smile turned cold. “Regardless, there are others I can threaten. Amatis, rise, and bring Jocelyn here.”