Alec was crouched in the shadows along the roof of a bank, a few blocks away from the Institute. His bow and a quiver full of arrows were slung over his back.

Next to him, Simon carried a similar weapon, and was studying a Sensor. "Definitely," he was saying. "This thing's vibrating like crazy."

"Okay," Alec said. He glanced over the edge of the roof, onto the street below. Jace, Clary, and Isabelle lingered at the side of the road, glamoured into invisibility. "Where?"

Simon spun around, squinting at the Sensor in his hand. "This way. I think."

Alec waved, catching Jace's attention. His parabatai glanced up, and Alec pointed in the direction Simon had indicated.

Jace nodded, and all five Shadowhunters started moving, Alec and Simon sticking to the roof. They made it almost two blocks without incident.

In the street below, Clary cried out, and Simon and Alec immediately grabbed for their bows. On the pavement, Clary, Izzy, and Jace were locked in battle with a monster.

Alec wasn't sure what else to call it. It was huge, with a hairy human body and a bull's head. Its nostrils glistened in the streetlights. Massive curved horns sprouted from its head.

"What the hell?" Simon asked. He was already firing arrows, aiming for the eyes and nose. The beast just shook them off.

Alec aimed for the ears, for the eyes, for the throat- but everything bounced off. He had never seen a demon like this before. Clary slashed at it with a seraph blade. A gash opened across the thing's chest, but it didn't vanish. Instead, it tipped its head back, roared, spun on its hooves, and took off.

Alec and Simon vaulted off the roof, landing next to their friends. Simon rested his hand on Isabelle's shoulder, scanning Clary for injuries. Alec moved toward Jace.

"Fine," Jace said. "I'm fine. What was that thing?"

"A Minotaur," Simon said. Everyone looked at him.

He shrugged. "What? I used to play Mythomagic."

"You are such a nerd," Isabelle said. "But I think you might be right."

"A Minotaur," Jace said. "Unbelievable."

"All the stories are true," Clary reminded him.

"Fair enough. We've got to find this thing." Jace scanned the surrounding street, his golden eyes alight. "Clary and Simon, you stay here. Check the surrounding streets, make sure it didn't stop somewhere. Isabelle, go back to the Institute, start sending fire-messages. Tell them to get in gear and start hunting. Alec and I will try to follow the thing. Text if you find anything," he added to Clary.

Alec knew how much it cost his parabatai, to leave Clary behind. But it was the best plan. Clary and Simon would be better together, the same way he and Jace were. Besides, the Minotaur had been headed toward Brooklyn, and if there was a monster in the streets, Jace knew Brooklyn was where Alec needed to be.

Isabelle didn't look happy about being left out of the action, but she didn't argue, just kissed Simon on the cheek and took off in the direction of the Institute. Jace squeezed Clary's hand, clapped Simon on the shoulder, and took off. Alec wished them both luck and followed.

"Where did this thing come from?" Jace asked. They were both running, but neither one was out of breath.

"I don't know," Alec said. "Weird stuff's been happening around here lately. You fighting those dog demons. Izzy told me she ran into two boys who disappeared into thin air."

"Yeah." Jace fished his Sensor out of his pocket. "By the Angel, this is going to take forever. Any chance you can convince your vampire friends to lend us a motorcycle or two?"

Alec sighed. "Come on. This way." He led Jace down a side street, a few blocks over to a heavily glamoured warehouse.

"The hell?" Jace asked.

"Don't tell anyone I showed you this," Alec said. "Lily will kill me. And you." He opened a small side door. Light from the street illuminated a vast empty space, with at least two dozen vampire motorcycles.

"In case of emergencies," Alec said. "Raphael set this place up."

"Never thought I'd say this," Jace said, "But thank the Angel for Raphael."

"I've said that before," Alec said. He swung his leg over the nearest bike. "Pick one."

Jace and Alec flew their bikes up, onto a catwalk and out a hole in the ceiling, carefully positioned so that no sunlight would ever reach the floor. They soared over Manhattan, keeping close to the ground, so the Sensor could continue to pick up the Minotaur's trail.

They flew over the river and into Brooklyn. Jace was frowning down at the Sensor as he directed them down a series of streets. Alec was worried; they were getting a little too close to home.

"Holy-" The Sensor exploded in Jace's hand. The force pushed Jace from the bike; he tumbled to the street as the motorcycle crashed into the side of a nearby building.

Alec swore under his breath and dove after Jace, pulling up at the last second, so the tires of his bike squealed against the pavement.

Jace had rolled the moment he struck the ground, and he was leaning against a wall, clutching at his arm.

"Broken," he said through gritted teeth. Alec reached for his stele, prying Jace's hand away to draw an iratze-

Someone screamed. "Look out!"

Alec reached for his bow.

"Go," Jace panted. He was rubbing at his arm, where the half-finished iratze stood out against his skin. "I'll join you."

Alec hesitated, then took off, jogging through the streets, listening. His heart sank as he rounded a corner.

He knew exactly where he was. Five doors down, his apartment building shone in the streetlight, his husband and kids inside. Between him and them, the Minotaur was battling two teenagers.

One was a boy with black hair and a bronze sword; the other, a blonde girl with a dagger. They danced around the Minotaur and each other, fighting as a team.

Alec drew his bow, nocked an arrow, and let it fly.

It sailed over the blonde girl's shoulder, and while the Minotaur was distracted by the boy, Alec's arrow plunged into its ear.

The Minotaur roared, and the teenagers both looked back at Alec. He drew another arrow and aimed for the Minotaur's eye.

The beast was already moving, charging at the blonde girl. She didn't scream; she leapt back and slashed her dagger across the Minotaur's snout. The Minotaur roared in pain and anger, rattling every window on the block.

The boy darted forward with his sword. Alec let three more arrows fly.

Behind him, the air began to glow. A doorway sketched itself into existence.

"Duck!" Alec cried. The boy glanced back, saw the door, and pulled the girl out of the way. Alec moved back as Magnus stepped out of thin air, the Portal closing behind him. Fire flew from his hands, slamming into the Minotaur and sending it tumbling back half a block.

"Honey, you didn't tell me we were having guests for dinner." Magnus winked at Alec.

"Please tell me the kids are asleep." Alec nocked another arrow.

"Are you kidding? You know whenever you go on patrol, they won't budge from the couch until you get back." Magnus's hands were glowing with blue fire. "Who are our friends?"

"No idea." The boy and girl had gotten back on their feet, and were facing down the Minotaur as it charged back up the street. "Wait, the kids are in there alone?"

"I sent your mother a fire-message. She Portalled in two minutes ago," Magnus said. "Really, what kind of parent do you take me for?"

Alec sighed in relief.

The Minotaur roared, and Alec lifted his bow. The girl was holding it off with her dagger; the boy seemed to be climbing one of the trees that had been planted along this street.

Magnus flexed his fingers. Blue lines of magic spread through the air, and Alec charged. He was used to fighting with magic on his side; he slipped through the lines as they wrapped themselves around the Minotaur.

Th Minotaur was lifted up into the air, struggling against Magnus's magic, as the boy leapt from the tree and landed on the Minotaur's back.

The beast roared, and the girl darted forward, slashing its legs and hooves as the boy wrapped his arms around its neck, sword pressed under its jaw. The Minotaur's eyes were wide, rolling back and forth.

Alec nocked five arrows in his bow and shot.

All five buried themselves in the Minotaur's eye.

The Minotaur bellowed, and then collapsed in on itself, exploding into a shower of dust that stuck to the boy and girl. The boy dropped from the air, landing on the pavement in a crouch.

"Thanks," he said. "I swear, that thing gets more annoying every time I fight it."

"No problem," Alec said slowly. He was aware of Magnus, moving to stand at his side. "Who are you?" Neither the boy nor the girl showed any sign of runes, and they didn't fight like Shadowhunters, either.

"Percy," the boy said. "This is Annabeth."

"Percy," Annabeth hissed.

"What? They saved our lives," Percy pointed out.

Annabeth didn't look convinced.

"I'm Alec" Alec said. "This is my husband, Magnus." Magnus lifted one hand in a wave, his rings sparkling.

"Nice to meet you," Percy said.

Just then, Jace sprinted around the corner, seraph blade lit. "Where is it?"

"Dead," Magnus said cheerfully.

"For now, at least," Annabeth added.

Alec raised his eyebrows. "Are you saying that thing could come back?"

"It will eventually," Percy confirmed. "We'll deal with it."

Jace shook his head. "So you killed it without me. Who are these two?"

"People who are leaving," Annabeth said. "Thank you for the help."

"See you around," Magnus said. "Tell Chiron I said hello, and he still owes me for that favor I did him back in Paris."

Annabeth's eyes narrowed. Percy's jaw dropped.

"Who did you say you were?" Annabeth asked

"Someone who should be getting home to his kids," Alec muttered. Magnus laughed.

"What he said."

Percy lifted one hand in a wave, and he and Annabeth started down the street, holding hands, heads bent together. Jace rolled his eyes.

"This city is getting more messed up every day. And I didn't even get to fight."

Alec laughed. "Go find Clary," he told Jace. "I know you're both worried sick."

Jace laughed. "I'll see you tomorrow."

"See you." Jace vanished into the shadows, leaving Alec alone with Magnus.

Alec arched an eyebrow. "Do I want to know?"

Magnus took Alec's hand. "I'll tell you. But we should probably get the kids to bed. You know how they run circles around your mother."

Alec nodded. "The work is never done."