“Simon—”

He dropped his voice. “If you don’t go, they’ll kill us both, and all this will have been for nothing. Go. Please.”

She nodded and turned away, Changing as she turned, so that one moment she was a slight human girl, her bead-tied braids bouncing on her shoulders, and the next she had hit the ground running on all fours, a swift and silent wolf. She darted from the clearing and vanished into the shadows.

Simon turned back to the vampires—and almost shouted out loud; Raphael was standing directly in front of him, inches away. Up close his skin bore the telltale dark traceries of hunger. Simon thought of that night in the Hotel Dumort—faces appearing out of shadow, fleeting laughter, the smell of blood—and shivered.

Raphael reached out to Simon and took hold of his shoulders, the grip of his deceptively slight hands like iron. “Turn your head,” he said, “and look at the stars; it will be easier that way.”

“So you are going to kill me,” Simon said. To his surprise he didn’t feel afraid, or even particularly agitated; everything seemed to have slowed down to a perfect clarity. He was simultaneously aware of every leaf on the branches above him, every tiny pebble on the ground, every pair of eyes that rested on him.

“What did you think?” Raphael said—a little sadly, Simon thought. “It’s not personal, I assure you. It’s as I said before—you are too dangerous to be allowed to continue as you are. If I had known what you’d become—”

“You’d never have let me crawl out of that grave. I know,” said Simon.

Raphael met his eyes. “Everyone does what they must to survive. In that way even we are just like humans.” His needle teeth slid from their sheaths like delicate razors. “Hold still,” he said. “This will be quick.” He leaned forward.

“Wait,” Simon said, and when Raphael drew back with a scowl, he said it again, with more force: “Wait. There’s something I have to show you.”

Raphael made a low hissing sound. “You had better be doing more than trying to delay me, Daylighter.”

“I am. There’s something I thought you should see.” Simon reached up and brushed the hair back from his forehead. It felt like a foolish, even theatrical, gesture, but as he did it, he saw Clary’s desperate white face as she stared up at him, the stele in her hand, and thought, Well, for her sake, at least I’ve tried.

The effect on Raphael was both startling and instantaneous. He jerked back as if Simon had brandished a crucifix at him, his eyes widening. “Daylighter,” he spat, “who did this to you?”

Simon only stared. He wasn’t sure what reaction he’d expected, but it hadn’t been this one.

“Clary,” Raphael said, answering his own inquiry, “of course. Only a power like hers would allow this—a vampire, Marked, and with a Mark like that one—”

“A Mark like what?” said Jacob, the slender blond boy standing just behind Raphael. The rest of the vampires were staring as well, with expressions that mingled confusion and a growing fear. Anything that frightened Raphael, Simon thought, was sure to frighten them, too.

“This Mark,” Raphael said, still looking only at Simon, “is not one of those from the Gray Book. It is an even older Mark than that. One of the ancients, drawn by the Maker’s own hand.” He made as if to touch Simon’s forehead but didn’t seem quite able to bring himself to do it; his hand hovered for a moment, then fell to his side. “Such Marks are mentioned, but I have never seen one. And this one …”

Simon said, “‘Therefore whosoever slayeth Cain, vengeance shall be taken on him sevenfold. And the Lord set a Mark upon Cain, lest any finding him should kill him.’ You can try to kill me, Raphael. But I wouldn’t advise it.”

“The Mark of Cain?” Jacob said in disbelief. “This Mark on you is the Mark of Cain?”

“Kill him,” said a redheaded female vampire who stood close to Jacob. She spoke with a heavy accent—Russian, Simon thought, though he wasn’t sure. “Kill him anyway.”

Raphael’s expression was a mix of fury and disbelief. “I will not,” he said. “Any harm done to him will rebound upon the doer sevenfold. That is the nature of the Mark. Of course, if any of you would like to be the one to take that risk, by all means, be my guest.”

No one spoke or moved.

“I thought not,” said Raphael. His eyes raked Simon. “Like the evil queen in the fairy tale, Lucian Graymark has sent me a poisoned apple. I suppose he hoped I would harm you, and reap the punishment that would follow.”

“No,” Simon said hastily. “No—Luke didn’t even know what I’d done. His gesture was made in good faith. You have to honor it.”

“And so you chose this?” For the first time there was something other than contempt, Simon thought, in the way Raphael was looking at him. “This is no simple protection spell, Daylighter. Do you know what Cain’s punishment was?” He spoke softly, as if sharing a secret with Simon. “‘And now thou art cursed from the earth. A fugitive and a wanderer shalt thou be.’”

“Then,” Simon said, “I’ll wander, if that’s what it comes to. I’ll do what I have to do.”

“All this,” said Raphael, “all this for Nephilim.”

“Not just for Nephilim,” said Simon. “I’m doing this for you, too. Even if you don’t want it.” He raised his voice so that the silent vampires surrounding them could hear him. “You were worried that if other vampires knew what had happened to me, they’d think Shadowhunter blood could let them walk in the daylight too. But that’s not why I have this power. It was something Valentine did. An experiment. He caused this, not Jace. And it isn’t replicable. It won’t ever happen again.”

“I imagine he is telling the truth,” said Jacob, to Simon’s surprise. “I’ve certainly known one or two of the Night Children who’ve had a taste of Shadowhunter in the past. None of them developed a fondness for sunlight.”

“It was one thing to refuse to help the Shadowhunters before,” said Simon, turning back to Raphael, “but now, now that they’ve sent me to you—” He let the rest of the sentence hang in the air, unfinished.

“Don’t try to blackmail me, Daylighter,” said Raphael. “Once the Night Children have made a bargain, they honor it, no matter how badly they are dealt with.” He smiled slightly, needle teeth gleaming in the dark. “There is just one thing,” he said. “One last act I require from you to prove that indeed you acted here in good faith.” The stress he put on the last two words was weighted with cold.

“What’s that?” Simon asked.

“We will not be the only vampires to fight in Lucian Graymark’s battle,” Raphael said. “So will you.”

Jace opened his eyes on a silver whirlpool. His mouth was filled with bitter liquid. He coughed, wondering for a moment if he was drowning—but if so, it was on dry land. He was sitting upright with his back against a stalagmite, and his hands were bound behind him. He coughed again and salt filled his mouth. He wasn’t drowning, he realized, just choking on blood.

“Awake, little brother?” Sebastian knelt in front of him, a length of rope in his hands, his grin like an unsheathed knife. “Good. I was afraid for a moment that I’d killed you a bit too early.”

Jace turned his head to the side and spat a mouthful of blood onto the ground. His head felt as if a balloon were being inflated inside it, pressing against the interior of his skull. The silvery whirling above his head slowed and stilled to the bright pattern of stars visible through the hole in the cave roof. “Waiting for a special occasion to kill me? Christmas is coming.”

Sebastian gave Jace a thoughtful look. “You have a smart mouth. You didn’t learn that from Valentine. What did you learn from him? It doesn’t seem to me that he taught you much about fighting, either.” He leaned closer. “You know what he gave me for my ninth birthday? A lesson. He taught me that there’s a place on a man’s back where, if you sink a blade in, you can pierce his heart and sever his spine, all at once. What did you get for your ninth birthday, little angel boy? A cookie?”

Ninth birthday? Jace swallowed hard. “So tell me, what hole was he keeping you in while I was growing up? Because I don’t remember seeing you around the manor.”

“I grew up in this valley.” Sebastian jerked his chin toward the cave exit. “I don’t remember seeing you around here either, come to think of it. Although I knew about you. I bet you didn’t know about me.”

Jace shook his head. “Valentine wasn’t much given to bragging about you. I can’t imagine why.”

Sebastian’s eyes flashed. It was easy to see, now, the resemblance to Valentine: the same unusual combination of silver-white hair and black eyes, the same fine bones that in another, less strongly molded face would have looked delicate. “I knew all about you,” he said. “But you don’t know anything, do you?” Sebastian got to his feet. “I wanted you alive to watch this, little brother,” he said. “So watch, and watch carefully.” With a movement so fast it was almost invisible, he drew the sword from its sheath at his waist. It had a silver hilt, and like the Mortal Sword it glowed with a dull dark light. A pattern of stars was etched into the surface of the black blade; it caught the true starlight as Sebastian turned the blade, and burned like fire.

Jace held his breath. He wondered if Sebastian merely meant to kill him; but no, Sebastian would have killed him already, while he was unconscious, if that were his intention. Jace watched as Sebastian moved toward the center of the chamber, the sword held lightly in his hand, though it looked to be quite heavy. His mind was whirling. How could Valentine have another son? Who was his mother? Someone else in the Circle? Was he older or younger than Jace?

Sebastian had reached the huge red-tinged stalagmite in the center of the room. It seemed to pulse as he approached, and the smoke inside it swirled faster. Sebastian half-closed his eyes and lifted the blade. He said something—a word in a harsh-sounding demon language—and brought the sword across, hard and fast, in a slicing arc.

The top of the stalagmite sheared away. Inside, it was hollow as a test tube, filled with a mass of black and red smoke, which swirled upward like gas escaping a punctured balloon. There was a roar—less a sound than a sort of explosive pressure. Jace felt his ears pop. It was suddenly hard to breathe. He wanted to claw at the neck of his shirt, but he couldn’t move his hands: They were tied too tightly behind him.

Sebastian was half-hidden behind the pouring column of red and black. It was coiling, swirling upward—“Watch!” he cried, his face glowing. His eyes were alight, his white hair whipping on the rising wind, and Jace wondered if his father had looked like that when he was young: terrible and yet somehow fascinating. “Watch and behold Valentine’s army!”

His voice was drowned out then by the sound. It was a sound like the tide crashing up the shore, the breaking of an enormous wave, carrying massive detritus with it, the smashed bones of whole cities, the onrush of a great and evil power. A huge column of twisting, rushing, flapping blackness poured from the smashed stalagmite, funneling up through the air, pouring toward—and through—the torn gap in the cavern roof. Demons. They rose shrieking, howling, and snarling, a boiling mass of claws and talons and teeth and burning eyes. Jace recalled standing on the deck of Valentine’s ship as the sky and earth and sea all around turned to nightmare; this was worse. It was as if the earth had torn open and hell had poured through. The demons carried a stench like a thousand rotting corpses. Jace’s hands twisted against each other, twisted until the ropes cut into his wrists and they bled. A sour taste rose in his mouth, and he choked helplessly on blood and bile as the last of the demons rose and vanished overhead, a dark flood of horror, blotting out the stars.

Jace thought he might have passed out for a minute or two. Certainly there was a period of blackness during which the shrieking and howling overhead faded and he seemed to hang in space, pinned between the earth and the sky, feeling a sense of detachment that was somehow … peaceful.

It was over too soon. Suddenly he was slammed back into his body, his wrists in agony, his shoulders straining backward, the stench of demon so heavy in the air that he turned his head aside and retched helplessly onto the ground. He heard a dry chuckle and looked up, swallowing hard against the acid in his throat. Sebastian knelt over him, his legs straddling Jace’s, his eyes shining. “It’s all right, little brother,” he said. “They’re gone.”

Jace’s eyes were streaming, his throat scraped raw. His voice came out a croak. “He said midnight. Valentine said to open the gate at midnight. It can’t be midnight yet.”

“I always figure it’s better to ask for forgiveness than permission in these sorts of situations.” Sebastian glanced up at the now empty sky. “It should take them five minutes to reach Brocelind Plain from here, quite a bit less time than it will Father to reach the lake. I want to see some Nephilim blood spilled. I want them to writhe and die on the ground. They deserve shame before they get oblivion.”

“Do you really think that the Nephilim have so little chance against demons? It’s not as if they’re unprepared—”

Sebastian dismissed him with a flick of his wrist. “I thought you were listening to us. Didn’t you understand the plan? Don’t you know what my father’s going to do?”

Jace said nothing.

“It was good of you,” said Sebastian, “to lead me to Hodge that night. If he hadn’t revealed that the Mirror we sought was Lake Lyn, I’m not sure this night would have been possible. Because anyone who bears the first two Mortal Instruments and stands before the Mortal Glass can summon the Angel Raziel out of it, just as Jonathan Shadowhunter did a thousand years ago. And once you’ve summoned the Angel, you can demand of him one thing. One task. One … favor.”