“Do you think we’re still in Idris?” Raphael asked.

“No,” Magnus said shortly. “We’re not in Idris. I can feel it in my blood.”

Luke looked at him. “Where are we?”

Magnus could feel the burn in his blood, the beginning of fever. It prickled along his nerves, drying his mouth, making his throat ache. “We’re in Edom,” he said. “A demon dimension.”

Raphael dropped the chain and swore in Spanish. “I cannot free you,” he said, clearly frustrated. “Why have Sebastian’s servants chained only you and not either of us?”

“Because Magnus needs his hands to do magic,” said Luke.

Raphael looked at Magnus, surprised. Magnus wiggled his eyebrows. “Didn’t know that, vampire?” he said. “I would have thought you would have figured it out by now; you’ve been alive long enough.”

“Perhaps.” Raphael sat back on his heels. “But I have never had much business with warlocks.”

Magnus gave him a look, a look that said: We both know that isn’t true. Raphael looked away.

“Too bad,” Magnus said. “If Sebastian had done his research, he would have known I can’t do magic in this realm. There’s no need for this.” He rattled his chains like Marley’s ghost.

“So this is where Sebastian’s been hiding all this time,” Luke said. “This is why we couldn’t track him. This is his base of operations.”

“Or,” said Raphael, “this is just some place he has abandoned us to die and rot.”

“He wouldn’t bother,” Luke said. “If he wanted us dead, we’d be dead, the three of us. He’s got some larger plan. He always does. I just don’t know why—” He broke off, looking down at his hands, and Magnus remembered him suddenly much younger, flyaway hair and worried looks and his heart on his sleeve.

“He won’t hurt her,” Magnus said. “Jocelyn, I mean.”

“He might,” Raphael said. “He is very crazy.”

“Why wouldn’t he hurt her?” Luke sounded as if he were holding in a fear that threatened to explode. “Because she’s his mother? It doesn’t work that way. Sebastian doesn’t work that way.”

“Not because she’s his mother,” Magnus said. “Because she’s Clary’s mother. She’s leverage. And he won’t give that up easily.”

They had been walking for what seemed like hours now, and Clary was exhausted.

The uneven ground made the walking harder. None of the hills were very high, but they were pathless, and covered in shale and jagged rock. Sometimes there were plains of sticky, tarry pitch to cross, and their feet sank in almost to the ankles, dragging down their steps.

They paused to put on runes for sure-footedness and strength, and to drink water. It was a dry place, all smoke and ashes, with the occasional bright river of molten rock sludging through the burned land. Their faces were already smeared with dirt and ash, their gear powdered with it.

“Ration the water,” Alec warned, capping his plastic bottle. They had paused in the shadow of a small mountain. Its jagged top snarled up into peaks and crenellations that made it resemble a crown. “We don’t know how long we’ll be traveling.”

Jace touched the bracelet on his wrist, and then his tracking rune. He frowned at the traced pattern on the back of his hand. “The runes we just put on,” he said. “Someone show me one.”

Isabelle made an impatient noise, then thrust out her wrist, where Alec had inked a speed rune earlier. She blinked down at it. “It’s fading,” she said, a sudden uncertainty in her voice.

“My tracking rune as well, and the others,” said Jace, glancing over his skin. “I think runes fade more quickly here. We’re going to have to be careful about using them. Check to make sure when they need to be applied again.”

“Our Speed runes are fading,” Isabelle said, sounding frustrated. “That could be the difference between two days of walking and three. Sebastian could be doing anything to the prisoners.”

Alec winced.

“He won’t,” Jace said. “They’re his insurance that the Clave will turn us over to him. He won’t do anything to them unless he’s sure that won’t happen.”

“We could walk all night,” Isabelle said. “We could use Wakefulness runes. Keep applying them.”

Jace glanced around. Dirt was smudged under his eyes, and across his cheeks and forehead where he’d rubbed the palm of his hand. The sky had deepened from yellow to dark orange, smeared with roiling black clouds. Clary guessed that meant that nightfall was near. She wondered if days and nights were the same in this place, or if the hours were different, the rotations of this planet subtly misaligned.

“When Wakefulness runes fade, you crash,” Jace said. “Then we’ll be facing Sebastian basically hungover—not a good idea.”

Alec followed Jace’s gaze around the deadly landscape. “Then we’re going to have to find a place to rest. Sleep. Aren’t we?”

Clary didn’t hear whatever Jace said next. She’d already moved away from the conversation, clambering up the steep side of a ridge of rock. The effort made her cough; the air was foul, thick with smoke and ash, but she didn’t feel like staying for an argument. She was exhausted, her head was pounding, and she kept seeing her mother, over and over, in her head. Her mother and Luke, standing on a balcony together, hand in hand, looking down at her fondly.

She dragged herself up to the top of the rise and paused there. It sloped down steeply on the other side, ending in a plateau of gray rock that stretched to the horizon, piled here and there with heaps of slag and shale. The sun had lowered in the sky, though it was still the same burned orange color.

“What are you looking at?” said a voice at her elbow; she started, and turned to find Simon there. He wasn’t quite as grimy as the rest of them—dirt never seemed to stick to vampires—but his hair was full of dust.

She pointed to dark holes where they pocked the side of the nearby hill like gunshot wounds. “Those are cave entrances, I think,” she said.

“Kind of looks like something out of World of Warcraft, doesn’t it?” he said, gesturing around them at the blasted landscape, the ash-torn sky. “Only, you can’t just turn it off to get away.”

“I haven’t been able to turn it off for a long time.” Clary could see Jace and the other Lightwoods a distance away, still arguing.

“Are you all right?” Simon asked. “I haven’t had a chance to talk to you since everything happened with your mother, and Luke—”

“No,” Clary said. “I’m not all right. But I have to keep going. If I keep going, I can not think about it.”

“I’m sorry.” Simon put his hands into his pockets, his head down. His brown hair blew across his forehead, across the place where the Mark of Cain had been.

“Are you kidding? I’m the one who’s sorry. For everything. The fact that you got turned into a vampire, the Mark of Cain—”

“That protected me,” Simon protested. “That was a miracle. It was something only you could do.”