A/N Hey all; here's my first TMNT fanfic and my first attempt at a published OC – as such, any and all reviews and suggestions are not only welcomed but encouraged. First chapter's kinda rough; please bear with me. Virtual cookie to anyone who can come up with a better title

Disclaimer: I own everything. Really. I do… Okay, fine, the only thing I own here is Frankie and the idea. *Sigh*

New York City, the Big Apple, the American Dream, whatever. You all know where it is. Full of hope, dreams, culture, and crime. The city that never sleeps.

Especially when you're a giant crime-fighting ninja turtle. There's always someone breaking the rules.

Tonight was no different.

But it was going to have to wait.

"Come on, Donnie, stop pokin' around and just fix the dang thing, will ya?"

"Raph, it's going to take me a little while to figure out the problem, and it'll take even longer if you don't stop bothering me. Go do something constructive. Or at least keep Mikey out of my lab."

Grumbling, a giant turtle with a red bandana and a grumpy expression stood up, stretched, and stalked off towards a TV. He wanted to get out on his bike, but there was something wrong with it. Huh, Mikey. He coulda sworn that Mikey had been messing around in the garage earlier; he'd probably broken the bike. Raph stalked off towards where Mikey would undoubtedly be blowing up aliens or something on his video games, fully intending to give him a piece of his mind. And maybe more.

"Yo, Mikey, what were you doin' in the garage earlier? 'Cause I swear, bro, if it was you who screwed up my bike, you're gonna be so dead…"

Back in the garage, a turtle wearing a purple mask shook his head in a combination of amusement and irritation. Typical day for a turtle, he thought. Raph's mad at Mikey, wow, what a shocker! Though he didn't think that whatever had happened to the bike was Mikey's fault. The orange-loving turtle knew better than to mess with Raph's bike.

He hoped.

Sighing, he went back to examining the mechanisms of the Shell Cycle. It wouldn't start for some reason. And Don, being the resident genius, had been rather roughly enlisted to fix the problem. His brothers were hopeless when it came to machines. Mikey didn't care about anything that wasn't a television, Raph had a tendency to believe that punching things was the solution to all life's problems, and Leo frankly couldn't be bothered to learn how a toaster worked, let alone a complicated piece of machinery like a vehicle. Don usually didn't mind, though, it was just that tonight he had something special he was researching that he really wanted to get back to.

Don heard a quiet scuffling sound from behind him, but dismissed it as Raph chasing Mikey around the lair. It wasn't exactly an uncommon occurrence.

He started paying attention, though, when he heard a metallic click. He dove to the side as there was a swish and a thunk and suddenly a knife was stuck in the floor right where his foot had been.

"What the shell?" he yelled, jumping up and drawing his bo in one movement. He caught movement out of the corner of his eye but who or whatever it was had dodged behind the armoured BattleShell by the time he had spun to look.

"Hey!" Don shouted. "Who's there?"

"What's going on, Donnie?"

Don turned. "Hey Leo, there's someone back behind the BattleShell," he said in a low voice. "Someone unfriendly."

Leo's eyes narrowed as he saw the knife still embedded in the floor. He drew one of his katanas and crept towards the armoured car. Whoever was throwing knives at his brother was as good as trapped, now; the BattleShell was parked up in the corner of the garage.

He leaped lightly onto the vehicle's roof, and heard a sharp intake of breath.

Out of nowhere, a knife whistled towards his head.

"Leo, look out!"

Leo deflected the blade easily, and caught the flash of dark hair moving for the door.

"Don!"

"On it!"

The bo met its target with a crack and a yelp. Leo flipped to his brother's side and looked down in surprise to see a woman – more a girl, really – staring back at him with a combination of fear and anger on her face.

Don straightened up. "Hey, it's just a kid."

The girl narrowed her eyes. "I ain't a kid, greenie. And if you're gonna kill me or somethin' make it quick, I don't got all day."

Don raised an eyebrow ridge. "Excuse me? May I remind you that you're the one trespassing here? In case you'd forgotten, you threw a knife at me!"

She scowled. "Better havin' to start a fight than caught unaware. You gonna kill me or not?"

"No."

"Huh?"

"I said no. Why do you expect us to kill you?"

"I dunno,"she shrugged, "that's what usually happens when ya get caught in someone else's turf, ain't it? 'Sides," she went on, "the hell he doin' with those freakin' swords if he ain't gonna use 'em to cut people up?" She jerked a thumb towards Leo.

The brothers exchanged a glance. Don had to admit she had a point. It still didn't explain why she had been the one to initiate the fight though.

"What are you doing here?" Leo's voice was rough.

She eyed him warily. "I ain't stealin' nothin'," she retorted defensively.

"Never said you were. I asked what you were doing in our garage."

Her chin jutted out defiantly. "I was just lookin' for a place to crash, didn't realize this spot was taken by a pair of – the hell are you, anyway?" she asked curiously.

"Turtles."

"You're screwin' with me, aren't ya? I mean, I heard of gators in the city, but talking turtles? That's a new one."

"I'm not kidding."

"Huh." She seemed to accept this without another thought. "Well," she huffed, jumping up, "you ain't gonna kill me, I'll just be on my way, then."

"Wait-" Don reached out a hand to stop her. In an instant there was a knife in her hand, and in another Leo's foot flashed out and caught her around the back. She squeaked and crumpled. The knife skittered away under the BattleShell.

Leo looked at the prone figure guiltily. "Oops."

Kneeling down, Don gently touched her neck. "She's got a pulse; you just knocked her out, Leo."

"I didn't think I had enough force behind that to knock someone out."

Don examined the girl more closely. He guessed that she couldn't have been older than fourteen or fifteen, and she was grimy and stick thin. He sighed. Obviously the kid didn't have any kind of home to go back to. She was in desperate need of a shower and a meal.

He couldn't just leave a homeless kid alone, unconscious, in the garage all night, even if she had tried to turn him into a turtle-kebab. "Leo, we're gonna have to take her back to the lair."

Leo looked at him incredulously. "You're joking. She attacked us, and – "

"And, Leo, you knocked her out. She said she was just looking for a place to sleep, she obviously doesn't have anywhere else to go."

Leo threw his hands in the air in exasperation. "Fine! She's your responsibility then, Donnie. And you're explaining to Master Splinter."

He nodded and picked the girl up carefully.