Hi! This is my first tmnt fanfiction, but I hope you like it! I'm keeping it in line with the 2012 tv series, but adding my own OC into the mix. I want to know people are actually reading the story though so review and PM me what you think!

Disclaimer: I do not own tmnt, just my OC

A dark figure crouched on the edge of the roof across the street from its target. The figure wore a black sleeveless hoodie zipped all the way up and tugged down to cover its face. Pale arms, lean with muscle reached down to hold the edge of the roof as the figure leaned forward, trying unsuccessfully to see in the darkness. The figure sighed before pulling its hood back and releasing long black hair from its confines.

The girl had delicate features that coincided with her slight, petite frame. She closed her eyes and breathed deeply. She thought of her past, the screams, the pain, and felt anger boiled up inside of her.

Her brows creased as she opened her eyes to glare down at the building, her eyes now yellow and pupils slitted like a cat's. A soft grinding noise echoed the vacant street as her nails lengthened and sharpened into claws.

Her pupils dilated, allowing her to see into the dark alley clearly. Her ears perked up, picking up the sound of approaching footsteps. She spun around to see four figures jumping across the roofs of the closely placed buildings. She immediately straightened and easily leapt across the street to another building, a normal feat for her amount of strength, and hid behind a ventilation shaft as the four figures stopped on the roof she was previously occupying.

She showed slight surprise when she peeked out from behind the shaft to get a good look at the newcomers, but she also knew better than to doubt her senses.

On the opposite roof stood four large green creatures that resembled turtles. One wore a purple mask and had a bo staff strapped across its shell. Another sported a red mask and had two sai holstered in its belt. A third wore an orange mask and its belt held a pair of nun chucks. The final turtle-like creature wore a blue mask and had twin katanas strapped on its shell.

She closed her eyes, focusing her hearing as she tried to listen in on them.

"Explain to me one more time what we're doing here," the orange-masked creature whispered to the blue-masked one. The other three groaned.

"Mikey, we've been over this," the blue-masked turtle replied, exasperated. "The building has the same logos as the van that was used to kidnap the family. So, if we wait here long enough, one of the kidnappers will eventually show his face, and when he does, we'll make him tell us where they took them."

"And then we got ourselves a van!" Mikey said excitedly, punching his fist into the air.

The girl face-palmed. How stupid was this turtle?

"Just hit the guy I tell you to," the blue-masked turtle replied after also face palming.

"Will do!"

"Are you sure this is gonna work?" the red-masked turtle asked.

"Trust me, they'll be here any second."

The girl narrowed her eyes. She didn't know who these turtles were, but she had been staking out this place for days, never sleeping and barely eating. She was exhausted and felt like she was on the brink of collapsing. There was no way that these creatures suddenly decide the watch the place and her enemies would finally show themselves.

The blue-masked one stood in the spot the girl previously occupied as the time slowly passed. She observed the purple-masked turtle and Mikey starting playing a paper football game when Mikey flicked the football into the other one's head, annoying his purple-masked companion. As more time passed, Mikey dozed off while sitting up and the purple-masked turtle starting jump roping before tripping and falling on its face. Another half an hour passed and three of the turtles stood on the other end of the roof, the purple-masked turtle and Mikey sitting back-to-back and playing I-spy.

"All right," Mikey said. "I'm thinking of something green; green, green."

"Is it Raphael again?" the purple-masked turtle asked, tired. This would be the tenth time Mikey used Raphael.

"Man! You're good at this!" Mikey exclaimed.

The girl across the street was barely holding back from smashing her head into the shaft in frustration. These turtle-things are so weird!

"Give it up all ready," Raphael said to his blue-masked comrade. "The guy is not going to show."

"We have to be patient," was the blue-masked turtle's reply.

Patience, yeah right. I've been here for over a week and haven't seen a thing.

"No! You have to come up with a better plan, because the four of us standing here with our thumbs up our noses-"

"I don't think they fit," Mikey commented. Raphael and the blue-masked turtle look at him before continuing.

"-is pointless!"

Just then the girl heard tires screeching below and lunged to peer down into the alley in disbelief.

"You sure about that Raph?" the blue-masked turtle asked.

What the hell! I've been here so long and this is when they decide to show up? This is ridiculous!

"He just showed up, didn't he? I should've complain two hours ago."

The van parked and the lights turned off as a grimy looking guy in a white tank top hopped out.

"Gentlemen," the blue-masked turtle started, his voice sounding deeper. "I have a bold and daring plan. There's no time for hesitation. My orders must be carried out without question."

By the time the leader finished his theatrical monologue, his companions had already leapt down to the street, leaving his alone.

"Guys? Guys, wait up."

She stopped listening as the turtles distracted the driver long enough for her to jump from the roof and land quietly on the ground next to the back doors of the van. She opened one door as she heard the man fire of his laser pistol. She quickly climbed inside and closed the door behind her. She crouched down between boxes as the van started and took off out of the alley with a lurch.

She barely managed to keep herself from slamming face first into the back of the van as the vehicle swerved left and right. She couldn't stop herself from smacking her head into the side of the van a few times and she fought the growing darkness creeping up on her. She hadn't slept for over a week, and she felt like she was on the verge of passing out every time she knocked her head against the metal siding.

A loud thud came from the roof as the van swerved again and something fell from the boxes and into her lap. It was a container of the glowing ooze she remembered all too well, but before she could think any further on the subject her head was smacked against metal again. She rubbed her head as she heard the pistol being discharged again.

Suddenly, she heard a tire burst and the van spun out of control and slammed into something hard before being thrown on its side. She was thrown haphazardly around, knocking her head hard enough to bring her to the brink of unconsciousness.

The doors of the van opened when the van came to a stop and she tumbled out along with a bunch of the boxes as she became buried under them. She groaned, fighting off the darkness that threatened to overtake her. She vaguely thought that next time she should take some cat naps during stake outs in the future.

She heard footsteps and looked through the cracks in the boxes to see the four turtle-like creatures standing at the back of the van. Raphael moved forward and opened the other van door and the canister of ooze fell out and rolled to a stop as Mikey's feet.

"Mom?" Mikey exclaimed, looking up in surprise.

"Woah," the four said together.

"So that's the -?" Leo started.

"Mutagen that turned us all into what we are now," Donnie finished, holding the canister up for him and his brothers to see.

"Let's drink some!" Mikey said excitedly.

"What?" Raph yelled. "Why would you do that?"

"Because if you mutate a mutant you get a super mutant!" Mikey explained like it was the most obvious thing in the world.

"Or a pile of goo on the sidewalk," Donnie interjected, staring blankly at his younger brother.

"Either way, it's an improvement," Raph said with his arms crossed and a smirk on his face.

"Guys, this is huge," Leo said, stepping in. "Whoever kidnapped those people is somehow connected to what happened to us fifteen years ago."

"How is that possible?" Donnie asked.

"For alien robots, anything is possible," Mikey said.

"Stop that. There are no such thing as alien robots!"

"Oh, yeah?" Mikey walked up to the grimy guy as he sat back. "Well, if there's no such thing as alien robots, how do you explain this!" Mikey pulled at the human's face to prove his point unsuccessfully.

"My face!" the man yelled.

"Man, this mask is glued on tight!"

"Mikey!" Leo yelled. "That's not a mask."

"Okay, he's in the clear." Mikey pushed the guy back. "But, those other guys were totally alien robots!"

"Enough!" Raph said, walking up to the human and grabbing his arm. "Time to get some answers. Who are you and what's going on?"

"The name's Snake," the man replied. "And I have nothing to say to you hideous freaks."

Well, that's because you don't know us yet." Raph threw the man towards his brothers. "See, we were just regular guys, that is, until we got his with a little of this." Two of his brothers held the man's arms as Raph opened the canister.

"W-What are you doing?"

"Playing a little game I like to called mutation roulette. Now, you could turn out handsome like me, or you could end up disgusting and deformed, like Mikey here."

"Hey!" Mikey said indignantly.

"So, you feel lucky?" Raph asked as he started to tip the canister.

"Okay, okay!" Snake yelled. "They call themselves the Kraang. They've been grabbing scientists from all over the city."

"Well, that worked pretty good," Leo said.

"Well of course it did," Raph replied. "Would you wanna look like Mikey?"

"I'm right here" Mikey said, pouting a little.

"What do they want with scientists?" Leo asked.

"I don't' know," Snake replied. Raph threatened Snake with the mutagen again. "All I know is that they're taking them out of the city tonight, but I don't know where!"

"This is awesome!" Donnie shouted. "That girl's dad's a scientist, I'm a scientist. Oh, she is so gonna like me!"

"I don't think you're here type," Snake dead-panned.

"Where are they know?" Leo asked, ignoring Donnie and Snake's exchange.

Snake was about to answer when they heard the boxes moving and being pushed aside. The five of them stared as a girl stood up and rubbed her head, then turned towards them.

"Aw, shell," Raph said. He thought they were spotted by a human, but that was until he got a closer look as she strode towards them.

"What they hell?" Snake exclaimed. "You weren't in there before!"

"No, I wasn't," the girl replied with an animalistic snarl that showed her sharp canines. Her yellow cat-like eyes narrowed at Snake, and completely ignored the turtles. "I was hitching a ride to find out where your base of operations was until these stupid turtle mutants interfered!" She glanced at each turtle individually - Leo looking surprised, Raph glaring back, Donnie looking sheepish, and Mikey looking scared.

"What the shell are you talking about?" Raph asked angrily.

The girl only his at him as she crouched, ready to pounce with her hands up in front of her showing them her sharp claws.

She lunged forward, but Raph moved out of her way, looking smug before he realized she planned for him to do that so she could reach her real target, Snake.

The force of her jump pushed Snake out of the grips of Donnie and Mikey and the girl and man rolled farther away before they stopped with her straddling him. Her arm was raised with her claws extended, ready to strike.

"Where are they holding the people?" she asked, growling loud enough to send a chill down even Raph's shell.

"Like I would tell a little girl like you," Snake replied. The girl's hand pounded the group next to his head, cracking the pavement as she brought her hand up for another strike as her knuckled bled. "Okay, I'll tell you!"

"I don't know about you, but I kinda like her," Raph said with a smirk. His brothers looked at him with disbelief. "What? That was cool!"

"She must be another mutant," Donnie reasoned. "Did you see her teeth?"

"She had claws too!" Mikey exclaimed.

"We'll worry about that later," Leo said. "For now let's just-" He turned to find the girl gone and Snake scrambling to get away. "What? Where'd she go?"

"Got him!" Raph shouted to his brothers as he tackled the man to the ground.

She leapt from roof to roof, taking a page from the turtles' book as she made her way to the Kraang base. Those turtles got in her way, and her rage fueled her and kept her awake and she landed on a building close to the base. She scoped the place out with her heightened sight and found at least twenty of the Kraang surrounding the place and a helicopter pad on the roof.

She growled low in her throat in annoyance. If only those turtles didn't get in her way, she would have made it inside the base no problem. Now, she was forced to fight her way in. Normally, she would scout the place out, but that could take nights and that Snake guy said they were moving the captives tonight. This was her only lead on the Kraang and she wouldn't let them get away - never again.

She spun as she felt a presence behind her, teeth bared and claws at the ready, only to find the turtles. Mikey squealed and hid behind Donnie, peeking out to watch her straighten up with narrowed eyes.

"What?" she asked as they stared at her. "Going to get in my way again, turtles?"

"Look, I think we got off on the wrong foot-" Leo started, but she cut him off.

"If it wasn't for you stupid turtles then I would have made into their base easily, but now I have to fight my way in with twenty Kraang guarding the place. I won't be able to babysit you guys too."

She spun and crouched on the ledge as she eyed the base again.

She heard the one named Leo walked up to stand on the ledge about ten feet from her position. He took out a telescope, before she spoke again.

"I already told you. There are about twenty Kraang armed with weapons and there's a helicopter pad on the roof."

Leo glanced at her, but looked through the eyeglass anyway.

"If you don't mind my asking, how do you know?" Donnie asked politely. She turned to look back at him.

"I can see," she replied simply before returning to her observations.

"But that's too far away," Donnie replied, confused.

"I thought you would have noticed by now," she said as she stood and turned to bodily face him.

Leo glanced at her warily and she stepped down from the ledge and slowing walked up to Donnie. Her baggy pants rustled as she grew closer and Raph took out his sai, anticipating an attack. Mikey cowered further behind Donnie, who gulped nervously and scratched his neck as she stopped right in front of him. He stood a head taller than her, so she grabbed his plastron and pulled him pulled to look her in the eye and he gasped. Her eyes were a brilliant yellow color, and her eyes had a slitted pupil instead of the usual round one.

Raph lunged to protect his brother when she bodily shoved Donnie in the way and the two turtles fell to the ground.

"You really didn't think you were the only mutants around did you?" she asked plainly as she returned to her perched on the ledge. Leo raised an eyebrow at her as he ran to help his younger brothers up.

"Well, Master Splinter is-"Mikey started before Raph hit him over the head, stopping him from speaking further. The turtles didn't know this mutant girl, and for all they knew she could be the enemy. Raph didn't need his baby brother talking about their sensei to a stranger, even if she was a mutant too.

"So, twenty Kraang," Leo commented, getting his brothers back on topic.

"And that's just the ones we can see," Donnie said.

"All right," Raph said, spinning his sai expertly. "An all-you-can-beat buffet."

"We can't just rush in there," Leo said, holding up his hand to stop his brother. "We need a plan."

"Why?" Raph asked, dumfounded.

"Think, you shell brain," Donnie said. "There are innocent lives at stake. If we screw this up they're all goners."

"Then we won't screw it up," Raph replied plainly.

"Boy I could sure go for some of that pizza now, huh?" Mikey said. The girl spun around. Mikey was previously guarding the man named Snake, and now he was nowhere to be seen. "What? I can't be the only one that's hungry."

As if on queue a small growl sounded and they looked over at the girl, who held her hand over her stomach sheepishly. They stared and she blushed in embarrassment, more pronounced on her pale skin.

"Before you guys got there, I was staking out the place for over a week," she mumbled. "I didn't eat or sleep in that time…"

"What?" Mikey shouted hyperly. "What's wrong with you? Are you insane?"

"Yeah, that's not healthy," Donnie said.

"Where's Snake?" Leo asked, once again bringing the group back on topic.

Before they could react, the girl snarled and leapt into action, running after Snake as he jumped off the roof, the turtles following close behind. She looked over the edge to see Snake running down the fire escape of the five story building. She followed after him, and jumped over the railing as she reached the third story, landing lightly on her feet. Unfortunately, when she looked up, Snake jumped down from the end of the fire escape and landed bodily on her.

She was knocked to the ground, stars dancing across her vision as the night seemed to grow darker. She realized her pupils changed back to their round shape and tried to regain her mutant vision, but to no avail. She noticed her claws and canines had also returned to normal as she jumped to her feet and chased after Snake.

The four turtles landed on the ground behind her as she turned the corner, catching up to Snake despite her human speed. They turned down an alley and Snake grabbed the lid of a garbage can and threw it at the girl. She didn't have enough time to react as it hit her square in the forehead and she fell hard on the ground.

Leo and Raph reached the wall and looked down the alley to find the girl unconscious, a thin trail of blood trailing down from a cut on her forehead with a garbage can lid lying beside her. Leo and Raph narrowed their eyes as they approached her cautiously, until they found she really was knocked out cold.

The duo heard movement from further in the alley, but Leo had a plan. Leo nodded towards the alley as he looked meaningfully at Raph.

"Oh great," Leo said in a terribly fake voice. "We let him get away."

"Woah, woah," Raph replied in a must more realistic voice. "You're the leader. That's means you let him get away."

"You're not helping."

"I'm not trying to help."

"Okay, look, you want me to lead? Fine. We go back to the lair, gear up, and at midnight, we drive Snake's van right up to the gate. They'll think we're him and we'll cruise right in."

"And then we bust some heads?" Raph asked hopefully.

"And then we bust some head," Leo replied.

"I love a happy ending," Raph said as he started to walk away when he tripped right over the girl, who groaned, but stayed unconscious. "Wait, what do we do with her?"

"I guess we should bring her back," Leo said slowly. In truth, he had actually forgotten about her. He knew Master Splinter told them to stay away from humans, and bathrooms, but she wasn't necessarily human, and she could help them against the Kraang. "Raph, you carry her."

"Wait, why do I have to carry her?" Raph asked angrily.

"You want me to lead?" Leo said smugly, crossing his arms over his chest. "Then you have to follow my orders. Plus, since you were the once that just kicked her, I think you should be the one to carry her." Raph didn't move, still fuming at his brother. "She isn't too heavy for you, is she, Raph? Because I could go get Mikey-"

Raph grumbled, but picked the petite girl up, supporting her shoulders and from under her knees. The brothers headed off back to the lair with a new guest to explain to Master Splinter.

Hope you enjoyed the story! So review so I know people are actually reading it and liking it!