Jace hurtled through the air, collided with a Dark Shadowhunter, and rode the Endarkened One’s body down to earth, dispatching him with a vicious scissoring blow. Somehow he had acquired a second blade; he wasn’t sure where. Everything was blood and fire singing in his head.

Jace had fought before, many times. He knew the chill of battle as it descended, the world around him slowing to a whisper, every movement he made precise and exact. Some part of his mind was able to push away the blood and pain and stink of it behind a wall of clear ice.

But this wasn’t ice; this was fire. The burn that coursed through his veins drove him on, sped his movements so that he felt as if he were flying. He kicked the headless corpse of the Dark Shadowhunter into the path of another, a red-clad figure flying toward him. She stumbled, and he sliced her neatly in half. Blood erupted across the snow. He was already soaked in it: he could feel his gear, heavy and sodden, against his body, and could smell the salt-iron tang, as if blood infused the air he was breathing.

He neatly jumped the dead Endarkened’s body and strode toward another of them, a brown-haired man with a tear in the sleeve of his red gear. Jace raised the sword in his right hand, and the man flinched, surprising him. The Dark Shadowhunters didn’t seem to feel much fear, and they died without screaming. This one, though, had his face twisted with fear—

“Really, Andrew, there’s no need to look like that. I’m not going to do anything to you,” said a voice behind Jace, sharp and clear and familiar. And just a touch exasperated. “Unless you don’t move out of the way.”

The brown-haired Shadowhunter darted hastily away from Jace, who turned, already knowing what he would see.

Sebastian stood behind him. He had arrived seemingly out of nowhere, though that didn’t surprise Jace. He knew Sebastian still possessed Valentine’s ring, which allowed him to appear and disappear at will. He wore red gear, worked all through with gold runes—runes of protection and healing and good luck. Gray Book runes, the kind his followers couldn’t wear. The red made his pale hair look paler, his grin a white slice across his face as his gaze scanned Jace from his head to his boots.

“My Jace,” he said. “Been missing me?”

In a flash Jace’s swords were up, both tips hovering just over Sebastian’s heart. He heard a murmur from the crowd around him. It seemed that both the Dark Shadowhunters and their Nephilim counterparts had paused their fighting to watch what was going on. “You can’t actually think I missed you.”

Sebastian raised his eyes slowly, his amused gaze meeting Jace’s. Eyes black like his father’s. In their lightless depths Jace saw himself, saw the apartment he had shared with Sebastian, the meals they had eaten together, jokes they had traded, battles they’d shared. He had subsumed himself in Sebastian, had given over his will entirely, and it had been pleasurable and easy, and down in the darkest depths of his treacherous heart, Jace knew that part of him wanted it again.

It made him hate Sebastian even more.

“Well, I can’t imagine why else you’re here. You know I can’t be killed with a blade,” Sebastian said. “The brat from the Los Angeles Institute must have told you that, at least.”

“I could slice you apart,” Jace said. “See if you can survive in tiddlywink-size pieces. Or cut off your head. It might not kill you, but it would be fun watching you try to find it.”

Sebastian was still smiling. “I wouldn’t try,” he said, “if I were you.”

Jace exhaled, his breath a white plume. Don’t let him stall you, his brain screamed, but the curse of it was that he knew Sebastian, knew him well enough that he couldn’t trust that Sebastian was bluffing. Sebastian hated to bluff. He liked to have the advantage and know it. “Why not?” Jace growled through clenched teeth.

“My sister,” said Sebastian. “You sent Clary off to make a Portal? Not very clever, separating yourselves. She is being held some distance from here by one of my lieutenants. Harm me, and her throat will be cut.”

There was a murmuring from the Nephilim behind him, but Jace couldn’t listen. Clary’s name pounded in the blood in his veins, and the place where Lilith’s rune had once connected him to Sebastian burned. They said it was better to know your enemy, but how did it help to know that your enemy’s one weakness was your weakness too?

The murmuring of the crowd rose to a roar as Jace began to lower his blades; Sebastian moved so quickly that Jace saw only a blur as the other boy whipped around and kicked out at Jace’s wrist. The sword fell from his right hand’s numb grasp, and he threw himself backward, but Sebastian was faster, drawing the Morgenstern blade and slashing out at Jace with a blow that Jace managed to evade only by twisting his whole body to the side. The tip of the sword sliced a shallow gash across his ribs.

Now some of the blood on his gear was his own.

He ducked as Sebastian slashed out at him again, and the sword whistled past his head. He heard Sebastian curse and came up with his own blade swinging. The two clashed together with the sound of ringing metal, and Sebastian grinned. “You can’t win,” he said. “I’m better than you, always have been. I might be the best.”

“Modest, too,” Jace said, and their swords slid apart with a grinding noise. He moved back, just enough to get range.

“And you can’t hurt me, not really, because of Clary,” Sebastian went on, relentless. “Just like she couldn’t hurt me because of you. Always the same dance. Neither of you willing to make the sacrifice.” He came at Jace with a side swing; Jace parried, though the force of Sebastian’s blow sent a shock up his arm. “You’d think, with all your obsession with goodness, that one of you would be willing to give up the other for a greater cause. But no. Love is essentially selfish, and so are both of you.”

“You don’t know either of us,” Jace gasped; he was breathing hard now, and knew he was fighting defensively, fending off Sebastian rather than attacking. The Strength rune on his arm was burning, flaring up the last of its power. That was bad.

“I know my sister,” said Sebastian. “And not now, but soon enough I’ll know her every way you can know someone.” He grinned again, feral. It was the same look he’d worn so long ago, on a summer night outside the Gard, when he’d said, Or maybe you’re just angry because I kissed your sister. Because she wanted me.

Nausea rose up in Jace, nausea and rage, and he flung himself at Sebastian, forgetting for a moment the rules of swordplay, forgetting to keep the weight of his grip evenly distributed, forgetting balance and precision and everything but hate, and Sebastian’s grin widened as he stepped out of the way of the attack and neatly kicked Jace’s leg out from under him.

He went down hard, his back colliding with the icy ground, knocking the breath out of him. He heard the whistle of the sword before he saw it, and rolled to the side as the Morgenstern blade slashed into the ground where he’d been a second before. The stars swung crazily overhead, black and silver, and then Sebastian was standing over him, more black and silver, and the sword came down again, and he rolled to the side, but he wasn’t fast enough this time and he felt it drive down into him.

The agony was instant, clear and clean as the blade slammed into his shoulder. It was like being electrified—Jace felt the pain through his entire body, his muscles contracting, his back arcing off the ground. Heat seared through him, as if his bones were being fused to charcoal. Flame gathered and coursed through his veins, up his spine—

He saw Sebastian’s eyes widen, and in their darkness he saw himself reflected, sprawled on the red-black ground, and his shoulder was burning. Flames licked up from the wound like blood. They sparked upward, and a single spark ran up along the Morgenstern blade, blazing into the hilt.

Sebastian swore and jerked his hand back as if he had been stabbed. The sword clanged to the ground; he lifted his hand and stared at it. And even through his daze of pain, Jace could see that there was a black mark, a burn across the palm of Sebastian’s hand, in the shape of the grip of a sword.

Jace began to struggle up onto his elbows, though the movement sent a wave of pain through his shoulder so severe, he thought he might pass out. His vision darkened; when it came back again, Sebastian was standing over him with a snarl twisting his features, the Morgenstern sword back in his hand—and the two of them were surrounded by a ring of figures. Women, gowned in white like Greek oracles, their eyes leaping orange flames. Their faces were tattooed with masks, as delicate and winding as vines. They were beautiful and terrible. They were Iron Sisters.

Each of them held a sword of adamas, point-down. They were silent, their mouths set in grim lines. Between two of them stood the Silent Brother whom Jace had seen earlier, fighting on the plain, his wooden staff in hand.

“In six hundred years we have not abandoned our Citadel,” said one of the Sisters, a tall woman whose hair fell in black ropes to her waist. Her eyes blazed, twin furnaces in the darkness. “But the heavenly fire calls us, and we come. Move away from Jace Lightwood, Valentine’s son. Harm him again, and we destroy you.”

“Neither Jace Lightwood nor the fire in his veins will save you, Cleophas,” Sebastian said, sword still in hand. His voice was steady. “The Nephilim have no savior.”

“You did not know to fear the heavenly fire. Now you do,” said Cleophas. “Time to retreat, boy.”

The tip of the Morgenstern sword lowered toward Jace—lowered—and with a cry Sebastian lunged forward. The sword whistled past Jace and buried itself in the earth.

The earth seemed to howl as if mortally wounded. A tremor ripped through the ground, spreading out from the tip of the Morgenstern sword. Jace’s vision was coming and going, consciousness bleeding out of him like the fire that bled from his wound, but even as the darkness came down, he saw the triumph on Sebastian’s face, and heard him begin to laugh as with a sudden terrible wrenching the earth tore itself apart. A great black rift opened beside them. Sebastian leaped into it and vanished.

“It’s not that simple, Alec,” Jia said tiredly. “Portal magic is complicated, and we’ve heard nothing from the Iron Sisters to indicate that they need our assistance. Besides, after what happened in London earlier today, we need to be here, on alert—”

“I’m telling you, I know,” Alec said. He was shivering, despite his gear. It was cold on the Gard Hill, but it was more than that. In part it was shock, at what Isabelle had said to his parents, at the look on his father’s face. But more of it was apprehension. Cold foreboding was dripping down his spine like ice. “You don’t understand the Endarkened; you don’t understand what they’re like—”

He doubled over. Something hot had lanced through him, through his shoulder down through his guts, like a spear of fire. He hit the ground on his knees, crying out.

“Alec—Alec!” The Consul’s hands were on his shoulders. He was distantly aware of his parents running toward him. His vision swam with agony. Pain, overlapping and doubled because it wasn’t his pain at all; the sparks under his rib cage didn’t burn in his body but in someone else’s.

“Jace,” he ground out between his teeth. “Something’s happened—the fire. You have to open a Portal, quickly.”

Amatis, flat on her back on the ground, laughed. “You won’t kill me,” she said. “You haven’t got the backbone.”

Clary, breathing hard, nudged the tip of the sword under Amatis’s chin. “You don’t know what I’m capable of.”

“Look at me.” Amatis’s eyes glittered. “Look at me and tell me what you see.”

Clary looked, already knowing. Amatis didn’t look exactly like her brother, but she had the same jawline, the same trustworthy blue eyes, the same brown hair touched with gray.

“Mercy,” Amatis said, raising her hands as if to ward off Clary’s blow. “Will you give it to me?”

Mercy. Clary stood frozen, even as Amatis looked up at her with obvious amusement. Goodness is not kindness, and there is nothing crueler than virtue. She knew she should cut Amatis’s throat, wanted to, even, but how to tell Luke she had killed his sister? Killed his sister while she’d lain on the ground, begging for mercy?

Clary felt her own hand shake, as if it were disconnected from her body. Around her the sounds of battle had dimmed: she could hear shouts and murmurs but didn’t dare turn her head away to see what was going on. She was focused on Amatis, on her own grip on the hilt of Heosphoros, of the thin trickle of blood that ran from beneath Amatis’s chin, where the tip of Clary’s sword had pierced the skin—

The earth erupted. Clary’s boots slipped in the snow, and she was flung to the side; she rolled, barely managing not to slice herself on her own blade. The fall knocked the breath from her, but she scrambled back, clutching Heosphoros as the ground shook around her. Earthquake, she thought wildly. She clutched at a rock with her free hand as Amatis rolled to her knees, looking around with a predatory grin.

There were screams all around, and an awful ripping noise. As Clary stared in horror, the ground tore itself in half, a massive crack opening in the earth. Rocks, dirt, and jagged chunks of ice rained down into the gap as Clary scrambled to get away from it. It was widening quickly, the jagged crack becoming a vast chasm with sheer sides that dropped away into shadow.

The ground was beginning to stop shaking. Clary heard Amatis laugh. She looked up and saw the older woman rise to her feet, grinning mockingly at Clary. “Give my brother all my love,” Amatis called, and jumped into the chasm.

Clary jolted to her feet, her heart pounding, and ran to the edge of the crack. She stared down over it. She could see only a few feet of sheer earth and then darkness—and shadows, moving shadows. She turned to see that everywhere across the battlefield the Endarkened were running toward the chasm and leaping into it. They reminded her of Olympic divers, sure and determined, confident of their landing.

The Nephilim were scrambling to get away from the chasm as their red-clad enemies dashed past them, throwing themselves into the pit. Clary’s gaze tracked among them, anxious, looking for one particular black-clad figure, one head of bright hair.

She stopped. There, just at the right of the chasm, some distance from her, were a group of women dressed in white. The Iron Sisters. Through gaps between them, Clary could see a figure on the ground, and another, this one in parchment robes, bent over him—

She broke into a run. She knew she shouldn’t run with an unsheathed blade, but she didn’t care. She pounded across the snow, darting out of the way of running Endarkened, weaving through the Nephilim, and here the snow was bloody and soaked and slippery, but she ran on anyway, until she burst through the circle of the Iron Sisters and reached Jace.

He was on the ground, and her heart, which had felt as if it were exploding inside her chest, slowed its beating slightly when she saw that his eyes were open. He was very pale, though, and breathing harshly enough that she could hear it. The Silent Brother was kneeling next to him, long pale fingers unsnapping the gear at Jace’s shoulder.

“What’s going on?” Clary asked, looking around wildly. A dozen Iron Sisters gazed back, impassive and silent. There were more Iron Sisters as well, on the other side of the chasm, watching unmoving as the Endarkened threw themselves into it. It was eerie. “What happened?”

“Sebastian,” Jace said through gritted teeth, and she dropped down beside him, across from the Silent Brother, as his gear peeled away and she saw the gash in his shoulder. “Sebastian happened.”

The wound was weeping fire.

Not blood but fire, tinged gold like the ichor of angels. Clary took a ragged breath and looked up to see Brother Zachariah looking back at her. She caught a single glimpse of his face, all angles and pallor and scars, before he drew a stele from his robe. Instead of setting it to Jace’s skin, as she would have expected, he set it to his own and carved a rune into his palm. He did it quickly, but Clary could feel the power that came from the rune. It made her shudder.

Stay still. This will end the hurt, he said in his soft omnidirectional whisper, and placed his hand over the fiery gash on Jace’s shoulder.

Jace cried out. His body half-lifted off the ground, and the fire that had bled like slow tears from his wound rose as if gasoline had been poured on it, searing up Brother Zachariah’s arm. Wildfire consumed the parchment sleeve of Zachariah’s robe; the Silent Brother jerked away, but not before Clary saw that the blaze was rising, consuming him. In the depths of the flame, as it wavered and crackled, Clary saw a shape—the shape of a rune that looked like two wings joined by a single bar. A rune she had seen before, standing on a rooftop in Manhattan: the first rune not from the Gray Book that she had ever visualized. It flickered and disappeared, so quickly that she wondered if she had imagined it. It seemed to be a rune that appeared to her in times of stress and panic, but what did it mean? Was it meant to be a way to help Jace—or Brother Zachariah?

The Silent Brother fell back silently into the snow, collapsing like a burned tree shivering to ashes.

A murmur tore through the ranks of the Iron Sisters. Whatever was happening to Brother Zachariah, it wasn’t supposed to be happening. Something had gone horribly wrong.

The Iron Sisters moved toward their fallen brother. They blocked Clary’s view of Zachariah as she reached for Jace. He was bucking and spasming on the ground, his eyes closed, his head tilted back. She looked around wildly. Through the gaps between the Iron Sisters she could see Brother Zachariah, thrashing on the ground: His body was shimmering, sizzling with fire. A cry burst from his throat—a human noise, the cry of a man in pain, not the silent mind-whisper of the Brothers. Sister Cleophas caught at him—parchment robes and fire, and Clary could hear the Sister’s voice rising, “Zachariah, Zachariah—”

But he was not the only one wounded. Some of the Nephilim were grouped around Jace, but many of the others were with their injured comrades, administering healing runes, searching their gear for bandages.

“Clary,” Jace whispered. He was trying to struggle up onto his elbows, but they wouldn’t hold him. “Brother Zachariah—what’s happened? What did I do to him—”

“Nothing. Jace. Lie still.” Clary sheathed her blade and fumbled his stele from his weapons belt with numb fingers. She reached to press the tip to his skin, but he writhed away from her, his body jerking.

“No,” he gasped. His eyes were huge and burning gold. “Don’t touch me. I’ll hurt you, too.”

“You won’t.” Desperate, she threw herself on top of him, the weight of her body bearing him backward into the snow. She reached for his shoulder as he twisted under her, his clothes and skin blood-slippery and fire-hot. Her knees slid to either side of his hips as she threw her full weight against his chest, pinning him down. “Jace,” she said. “Jace, please.” But his eyes wouldn’t focus on her, his hands spasming against the ground. “Jace,” she said, and put the stele to his skin, just over his wound.

And she was on the ship again with her father, with Valentine, and she was throwing everything she had, every bit of strength, every last atom of will and energy into crafting a rune, a rune that would burn down the world, that would reverse death, that would make the oceans fly up into the sky. Only, this time it was the simplest of runes, the rune every Shadowhunter learned in their first year of training:

Heal me.

The iratze took shape on Jace’s shoulder, the color spiraling from the tip so black that the light coming from the stars and the Citadel seemed to vanish into it. Clary could feel her own energy vanishing into it too as she drew. Never had she felt more like the stele was an extension of her own veins, that she was writing in her own blood, as if all the energy in her was being drawn out through her hand and fingers, her vision darkening as she fought to keep the stele steady, to finish the rune. The last thing she saw was the great burning whirl of a Portal, opening onto the impossible sight of Angel Square, before she slid into nothingness.