The unfamiliar blade was heavy in Jace’s hand. He preferred to use his left arm, but the sword had a right-handed grip. The weapon was dented around the sides, as if it had seen quite a few battles. He wished he had one of his own weapons in his hand—

It appeared all at once, rising up in front of them like a fish breaking the surface of water with a sudden silver glint. Jace had seen the Adamant Citadel before only in pictures. Carved out of the same stuff as seraph blades, the Citadel glowed against the night sky like a star; it was what Jace had mistaken for the light of a bonfire. A circular wall of adamas ringed it, with no opening in the wall except a single gate, formed of two huge blades plunged into the ground at angles, like an open pair of scissors.

All around the Citadel the volcanic ground stretched away, black and white like a chessboard—half volcanic rock and half snow. Jace felt the hairs rise on the back of his neck. It was like being at the Burren again, though he remembered that only the way one might remember a dream: Sebastian’s dark Nephilim, in their red gear, and the Nephilim of the Clave, in black, blade to blade, the sparks of battle rising into the night, and then the fire of Glorious, wiping out all that had gone before.

The earth of the Burren had been dark, but now Sebastian’s warriors stood out like drops of blood against the white ground. They were waiting, red under the light of the stars, their dark blades in their hands. They stood between the Nephilim who had come through the Portal, and the gates of the Adamant Citadel. Though the Endarkened were at a distance, and though Jace could not see any of their faces clearly, he could somehow feel them smiling.

And he could feel too the unease in the Nephilim around him, the Shadowhunters who had come through the Portal so confident, so ready for battle. They stood and looked down at the Endarkened, and Jace could feel the hesitation in their bravado. At last—too late—they felt it: the alienness, the difference of the Endarkened. These were not Shadowhunters who had temporarily strayed from the path. They were not Shadowhunters at all.

“Where is he?” Clary whispered. Her breath was white in the cold. “Where’s Sebastian?”

Jace shook his head; many of the red-geared Shadowhunters had their hoods up, and their faces were invisible. Sebastian could have been any one of them.

“And the Iron Sisters?” Clary searched the plain with her gaze. The only white was snow. There was no sign of the Sisters in their robes, familiar from many Codex illustrations.

“They’ll stay inside the Citadel,” Jace said. “They have to protect what’s inside it. The arsenal. Presumably that’s what Sebastian’s here for—the weapons. The Sisters will have surrounded the interior armory with their bodies. If he manages to get through the gates, or his Endarkened do, the Sisters will destroy the Citadel before they let him have it.” His voice was grim.

“But if Sebastian knows that, if he knows what the Sisters will do—” Clary began.

A scream cut the night like a knife. Jace started forward before realizing the scream was coming from behind them. Jace whirled to see a man in worn gear go down with the blade of a Dark Shadowhunter in his chest. It was the man who had called out to Clary in Alicante, before they had reached the Gard.

The Dark Shadowhunter whirled, grinning. There was a cry from the Nephilim, and the blonde woman Clary had heard speaking excitedly at the Gard stepped forward. “Jason!” she cried, and Clary realized she was speaking to the Endarkened warrior, a thickset man with the same blonde hair she had. “Jason, please.” Her voice trembled as she moved forward, stretching out her hand to the Endarkened, who drew another blade from his belt, looking at her expectantly.

“Please, no,” Clary said. “Don’t—don’t go near him—”

But the blonde woman was only a step away from the Dark Shadowhunter. “Jason,” she whispered. “You’re my brother. You’re one of us, a Nephilim. You don’t have to do this—Sebastian can’t force you. Please—” She looked around, desperate. “Come with us. They’re working on a cure; we’ll fix you—”

Jason laughed. His blade flashed out, a sideways slash. The blonde Shadowhunter’s head fell. Blood fanned out, black against the white snow, as her body slumped to the ground. Someone was screaming over and over, hysterically, and then someone else cried out and gestured wildly behind them.

Jace looked up and saw a line of Endarkened advancing from behind, from the direction of the closed Portal. Their blades flashed out in the moonlight. The Nephilim began to stumble down the ridge, but it was no longer an orderly progression—there was panic among them; Jace could feel it, like the taste of blood on the wind. “Hammer and anvil!” he shouted, hoping they would understand. He seized Clary with his free hand and yanked her back, away from the headless body on the ground. “It’s a trap,” he shouted at her over the noise of the fighting. “Get to a wall, somewhere you can make a Portal! Get us out of here!”

Her green eyes widened. He wanted to grab her, kiss her, cling on to her, protect her, but the fighter in him knew he had brought her into this life. Encouraged her. Trained her. When he saw the understanding in her eyes, he nodded and let her go.

Clary pulled away from his grip, sliding past an Endarkened warrior who was facing off against a staff-wielding Silent Brother in bloody parchment robes. Her boots skidded on the snow as she darted toward the Citadel. The crowd swallowed her up just as an Endarkened warrior drew his weapon free and lunged for Jace.

Like all Endarkened Shadowhunters, his motions were blindingly swift, almost feral. As he rose up with his blade, he seemed to blot out the moon. And Jace’s blood rose up too, shooting like fire through his veins as his awareness narrowed: There was nothing else in the world, only this moment, only the weapon in his hand. He leaped toward the Dark Shadowhunter, his sword outstretched.

Clary bent to retrieve Heosphoros from where it had fallen in the snow. The blade was smeared with blood, the blood of a Dark Shadowhunter who was even now darting away from her, flinging himself back into the battle churning on the plain.

It had happened now a half dozen times. Clary would attack, attempt to engage one of the Endarkened in a fight, and they would drop their weapons, back away, turn from her as if she were a ghost, and hurry away. The first time or two she had wondered if they were afraid of Heosphoros, confused by a blade that looked so much like Sebastian’s. She suspected something else now. Sebastian had probably told them not to touch her or hurt her, and they were obeying.

It made her want to scream. She knew she should fling herself after them when they ran, end them with a blade to the back, or a slice to the throat, but she couldn’t bring herself to do it. They still looked like Nephilim, human enough. Their blood ran red onto the snow. It still felt like cowardice to attack someone who could not attack back.

Ice crunched behind her, and she spun, her blade out. Everything had happened in a rush: the realization that there were twice as many Endarkened as they had counted on, that they were besieged on two sides, Jace’s plea to her to make a Portal. She was fighting her way through a desperate crowd now. Some Shadowhunters had scattered, and some had planted themselves where they were, determined to fight. As a mass they were being slowly pushed down the hill toward the plain, where the battle was at its thickest, bright seraph blades flashing out against dark knives, a mix of black and white and red.