A/N: So here's the deal people. I am going to alternate writing chapters for my crossovers as follows:

Not What They Seem (this one)

City of Gods (Percy Jackson/Mortal Instruments)

Leo Gets Out-fired (Percy Jackson/Inheritance) – no chapters yet

Jace Gets Grumpy When He's Forced to Babysit (Mortal Instruments/Harry Potter) – no chapters yet

Light, Dark and Magic (Percy Jackson/Harry Potter) – no chapters yet

Percy Jackson and the Wolves of Beacon Hills (Percy Jackson/Teen Wolf)

City of Dragonfire (Mortal Instruments/Inheritance)

Hera's Interfering Again (Percy Jackson/Inheritance)

Don't know how often I'll be updating but I'll try not to leave anyone waiting for too long.

Set after CoHF, and post Season 6 (AU where people still don't know about the supernatural despite the events of Season 6B). I own nothing.

Jace and Clary were just trying to get some alone time when Isabelle came barging into his room.

"Haven't you heard of knocking?" Jace snapped, but Isabelle just ignored him.

"Mom wants to see us in the library," she said shortly. "Now," she added when neither of them made any effort to move.

Groaning, Jace and Clary stood and followed Isabelle out of the room and toward the library.

"This had better be good," Jace muttered, before asking Isabelle why they'd been summoned.

"Not a clue," she said. "Mom just said to find you two and phone Alec, and get you all to come to the library."

When they arrived in the library, Maryse was sat at the desk that Hodge had used when he'd lived at the institute. She was lightly drumming her fingers on the desk. She looked nervous. Like she was going to have to give them some bad news that she'd only just heard herself. Jace wracked his brain for what could have her so worked out. It couldn't be Valentine or Sebastian, as they were both categorically dead. He'd watched it happen. Watched the boy that Sebastian had deserved to be, die after the evil was burned out of him. It wasn't Sebastian Morgenstern who had died. It was green-eyed Jonathan Morgenstern, the brother that Clary had deserved. She still had nightmares about that. Nightmares that started out as pleasant dreams where she lived as a happy family with Jocelyn, Luke and Jonathan. Nightmares that ended with her stabbing her brother through the heart.

"What's wrong, Mom?" Isabelle asked.

"Wait for Alec," Maryse said. As if on cue, Alec walked in.

"What's going on?" he asked.

"Now that the four of you are here, the Clave has a job for you," Maryse said.

"The Clave?" Jace questioned. "Not you?"

"I don't agree with it, but the Clave insisted. We have received reports of supernatural activity in a town called Beacon Hills, in California. The reports don't entirely make sense and seem to be centred around the high school, which they want you to infiltrate. That's why there sending you, not anyone from Los Angeles. There aren't any shadowhunters of your age there – as you know, Julian Blackthorn and Emma Carstairs are too young. Jace, Clary and Isabelle, you will be enrolled as juniors, and Alec as a senior. I have been told to stress that this is an information-gathering mission, you are not to engage without obtaining authorisation from the Clave, unless absolutely necessary," Maryse said.

"Mundane high school?" Jace exclaimed. "Are you serious?"

"Unfortunately, yes I am," Maryse sighed. "You are to leave tomorrow, and join the school on Monday."

Jace turned and walked out. He heard Clary following him. "I can't believe it. We won two wars for those people and they send us out for an information-gathering mission under orders not to engage? Do they think we can't handle ourselves?"

"They wouldn't be sending us out alone if they thought that, Jace. Think of it this way, you'll have the chance to experience what my life was like before I met you. See what it's like to live a halfway normal life. Be normal," Clary said.

"Are you saying I'm not normal?" Jace teased.

"Jace Herondale, you aren't normal by anyone's standards. You're one of a kind," Clary said.

"No," he said. "We're two of a kind." He leant down to kiss her, but she rested her head against his chest.

"Mom's going to flip her shit," she said, making Jace laugh. "I'd better go and break the news to her in person. And you should stay here, or she might actually kill you."

"Jocelyn loves me," Jace objected, and now Clary laughed.

"She may not hate you like she used to, but she still blames you for everything Shadowhunter-y that happens to me," Clary said.

"But this isn't my fault."

"As far as she's concerned, it's all your fault, since you were the one who brought me into the shadow world. The only reason she hasn't killed you already is because I'm happy," Clary said.

"Well, at least she has her priorities straight," Jace sighed. "Your happiness is the most important thing in the world."

"Ugh, stop being so cliché," Clary said, kissing him lightly on the lips. "I'll see you tomorrow, for the adventure of a lifetime."

"I think 'adventure of a lifetime' was covered by our trip to hell," Jace started to say, but Clary was walking away.


Liam woke with the feeling of anticipation. It was the first day of Christmas break for anyone at college, and Scott and the rest of the pack would be coming back to Beacon Hills. Apparently, even Ethan and Jackson were going to be visiting from London with someone called Isaac, who Liam hadn't met. Scott had told him that he'd fallen of the radar after Allison (someone else Liam had never met, but who he knew a lot about) had died. Liam wondered whether Theo would visit. He had a complicated friendship with the pack but did his own thing most of the time, and Liam rarely knew where he was. He was really looking forward to seeing the pack. Mason and Corey were his best friends, but they weren't the same. Mason was human and Corey was a chimera. He was the only werewolf left in Beacon Hills. He was especially looking forward to Scott being back, so he could be in charge again. Scott was kind of like a bit brother, a strange relationship, he had to admit, considering that when they had met, Scott had broken his ankle of the lacrosse field, bitten him, and then kidnapped him. But Scott was his alpha. The one person he could go to for anything. Whether it was werewolf related or not.

He glanced at the clock, and realised that it was five to eleven. He was supposed to be at Scott's house in five minutes to help Melissa get ready for the welcome home meal. Everyone else would be there at one. Swearing, he grabbed his phone and dialled Melissa's number.

"Everything alright, Liam?" she asked as she picked up. They'd had a rocky relationship at first, but she seemed to have forgiven him for trying to kill Scott last year.

"Yeah, fine. I overslept. Just wanted to let you know I'll be a little late," he said.

"No problem, Liam. Just get here when you can," she said.

"Thanks, Melissa, I'll see you in a bit." He hung up, just as he fell over, trying to put some jeans on. He landed with a crash.

"Liam!" his mom shouted from downstairs. "You okay?"

"I'm good," he shouted back. "Just fell over." His parents had no idea that he was a werewolf, and that even if he hadn't been ok, he'd have healed by the time they made it upstairs. With his jeans on, he put on a pair of shoes and ran down the stairs. Before he could make it out the door, his mum came out of the kitchen.

"Liam, you're not wearing a shirt," she said, confused. Shit. Liam didn't really feel the cold anymore, and would often go for a run in the middle of the night wearing just a pair of shorts. It was bad enough that he was going to have to run to Scott's, which was on the opposite side of town, in his jeans. He'd been planning on using one of the jumpers he kept there. Since the events of the last couple of years, they'd decided to all get keys for Scott's, Stiles' and Lydia's houses, and all kept some clothes there, since they were the three whose parents knew about the supernatural, albeit Principal Martin seemed to not want to think about it if possible. He smiled sheepishly at his mom, hoping to convey the message that he hadn't realised, and grabbed a jumper from the banister.

"I'll see you later," he said as he ran out of the door. As soon as he'd gone round the corner, he took the jumper off, and tied it round his waist.

By the time he reached Scott's he was covered in sweat. He knocked on the door – they'd agreed to only use the keys in emergencies while Scott, Stiles and Lydia were away at college.

"Can I have a shower?" he asked, as soon Melissa opened the door.

"Sure, I wasn't expecting you so soon, given the phone call. Did you run?" Melissa said, emphasising the word run.

"I went through the preserve, not through town," Liam assured her. He knew that she was worried that he'd been seen running faster than should be humanly possible. Melissa was great. Once she'd gotten over his attempt to kill Scott, he'd begun to worry about him, and he would go to her if he needed a mom's advice about something supernatural. He smiled. This was actually happening. His pack was coming home.