AN: This came about as a result of it suddenly hitting me yesterday that both these series take place in NYC, and they both center around a group of kids with crazy abilities and weapons and stuff that go around kicking the asses of all sorts of insane creatures and just totally pwning in general, and I thought, "EXTREME CROSSOVER POTENTIAL!"

And, thus, Tessa Lennox and this X-over were both born.



UPDATE FROM THE NOT-SO-DISTANT FUTURE: Okay, when I created this girl, I had NO CLUE that there was already a character in the Infernal Devices books named Tessa, and once I found out, I was like, "Well...this is slightly awkward." SO, I changed her name to Lenore, and I didn't just pick that because of Poe, even though I am a HUGE fan of his work. I chose it because of a meaning it has, which will be explained eventually in some later chapter. Just wanted to let everyone know what's going on and how it came about! PX

Lenore Lennox's life had always been weird. She was dyslexic, had ADHD, and was constantly seeing weird things in her peripheral vision that were always gone when she turned to look at them directly, almost like there were halfway real shadow creatures or something that were there, but also weren't at the same time. Sometimes, she would have these weird blackout things, where it was as if she blinked, and suddenly, something had happened without her knowing it, almost like puzzle pieces of the universe falling into oblivion and leaving her staring in confusion at the blank spaces left behind.

But when she was singing or listening to her iPod, or, preferrably, singing along to her music? It was like becoming a completely different person, because when she had her music, no matter how brief the time she was getting with it, she was actually good at something for once. And she loved the way it felt. She cherished that feeling and the times when she was given the chance to feel it by immersing herself completely in the tune and letting the music surround and engulf and feeling it fill everything inside her completetly, right down to the marrow in her bones.

Except not everyone appreciated music like she did, and therefore some of them didn't appreciate her talent for it, and a handful of them even said it was stupid and had even asked her why she would even bother wasting her time with something so useless, and those people really irked her, and she would've jumped at the chance to punch a few of them in the face without any consequences, and there were also a couple very specific ones that she wouldn't have minded too much getting to knock some of their teeth out, or maybe give them a black eye, or, if she was really lucky, both.

Matthew was one of those very specific ones. And she wanted to punch him now more than she ever had before. Then it occured to her that maybe, since they weren't in school or anything, she could get away with at least slapping him or stomping on his foot or something. So that's exactly what she did; she picked up her one-inch binder with pictures of her favorite singers, celebrities, characters, and so forth on the front that had a piece of cardstock duct tape'd to the front with the words "TOUCH AND DIE" scrawled across it in thick black Sharpie, brought her foot down as hard as she could onto Matthew's, then grabbed her canvas messenger bag, slung it across her body, and put the binder into it as she calmly walked away and left Central Park.

And then nearly fell down the stairs leading down to the subway and cracked her skull open and maybe even broken her spine and died when four kids that looked about her own age pushed her and several other people out of their way as they went racing down into the subway. After they had passed her, Lenore saw one of the boys point in the same general direction of the tracks and heard him say, "Nico and Piper, you guys cover that end, Annabeth and I will take the other. C'mon, guys, we gotta move fast if we're gonna stop this psycho bitch, let's go!"

Lenore moved to stand with her back against the wall opposite the tracks, leaning against the graffiti-covered surface casually with one foot against it as she watched everything go down, trying to keep her face as neutral and indifferent as possible, doing her best to look as if she wasn't paying any attention to what was happening. In the next few moments, a girl with flaming hair, white skin, red eyes, fangs, a prosthetic leg made of what appeared to be bronze, and a donkey leg came around a corner making hissing and spitting noises that put Lenore under the impression that she was not too happy about something right then.

Right as one of the girls jumped the human-donkey-robot-cyborg-whatever-she-was from behind and drove a bronze-bladed dagger up to the hilt in her/its back, anotherquartet came from around the same corner the animal/human/cyborg had, these ones with their arms covered in really bizarre tattoos, three with blades that glowed white, and the fourth with a silver-gold whip held so tightly in one hand that her knuckles were on the verge of turning white. The group with the tattoos was dressed in strange black clothing, unlike the other group, who were dressed no differently than any other random teenager you might see on the street every day.

The blonde guy who was in the lead of the group Lenore was now mentally referring to as "Those Kids with the Weird Tats" went over to the guy who seemed to be the leader of what she was calling "Those Other Kids" and brought his hand down on the other guy's shoulder. He muttered something that Tessa couldn't quite hear very clearly, but that sounded suspiciously like, "That was our kill, asshole."

Finally, Lenore couldn't keep her curiosity at bay anymore and went over to them. "Hey, sorry to interrupt," she said, "but what the hell was that thing you just killed?" "She can see past the glamours!" the redhead blurted out in surprise, while at the exact same time, the girl from the other group with short choppy brown hair and the braid hanging on one side of her face with feathers woven into it cried, "She's not affected by the Mist!"

Then, from both of them, "She's one of us!"

Lenore stared at them. "Um...Okay, then," she said finally. The blonde guy and the dark-haired dude that were in Those Kids with the Weird Tats looked at each other. "We need to get her back to the Institute, ASAP," the blonde said. The other one nodded in agreement. "You're right," he said. The girl with stormy grey eyes from Those Other Kids stepped forward. "Whatever this Institute of yours is," she said, "she's not going there. She's coming with us back to our camp, where she belongs." The blonde guy frowned. "Alright then," he said. "Clearly, none of us is about to back down on this, so I guess there's only one way to settle it without having to maim, strangle, and kill each other; we let her decide for herself who she'll go with."

And they all turned to look expectantly at Lenore.

She suddenly felt very exposed and vulnerable as she nervously bit her lower lip and sort of shuffled her feet around, scuffing the toe of her already-scuffed-and-dirty combat boot against the ground and rubbing the back of her neck. "Well," she began slowly, "no offense or anything, but to tell the truth, when I hear someone say the word institute, I think of the mental kind. You know, as in like the wacky shack, the nuthouse, or whatever you wanna call it. Asylums, y'know? Pennhurst type stuff. So, sorry, but I think I'm gonna have to go with the camp. That sounds a lot more fun, not to mention, y'know, sane. Sorry."

The two guys in streetclothes high-fived with each other, then the one without the metal skull on his finger turned and offered his hand. "Greetings from Camp Half-Blood!" he said. "I'm Percy Jackson, that's my girlfriend Annabeth Chase, our friend Piper McLean, and my cousin Nico di Angelo." Tessa took the offered hand and shook it. "Eleanore Lennox, but I go by Lenore" she said. "So what's this Camp Half-Blood place?"

"We prefer to show the noobs rather than just tell 'em," Nico said, drawing his black sword and placing the tip of it against the ground. He shook some hair out of his eyes as he grinned lopsidedly. "Everybody put a hand on top of the hilt," he said. "It's shadow travelin' time, bitches." Percy's hand went on first, then Annabeth's on his, followed by Piper, and finally, Lenore, who hesitated to add hers until Annabeth gave her a small grin and nod of encouragement.

"Good afternoon, ladies and gentlemen," Nico said, "this is your captain speaking. Please keep all hands, feet, tentacles, claws, and/or any other appendages inside the vehicle at all times, puke over the side if you feel the need to do so at any point, hold on tight, and above all, sit back, relax, and enjoy the ride."

And then, at the last possible moment, the other group of teens put their hands on the sword and were taken along for that ride.

AN: Obviously, the Shadowhunters saw some kind of demon, not an empousa, but don't ask what kind, because I couldn't tell you even if I wanted to, which I kind of did while writing this, to tell the truth. :/