This is from TMNT 2012, which is owned by Nickelodeon. And this is my first written story, so feedback would be great.

Anastasia walked along the dirty, snowy, streets of New York humming.

It was her 14th birthday the next day, and she would finally be able to get a job. Most 14 year olds wouldn't even dream of being happy for such a thing, but Anastasia was an orphan who lived in an alleyway; she needed the money. She thought of all the food she could get that WASN'T from a trashcan, a new blanket, maybe some clothes. And defenitely a little bed for Monseuir, her pet mouse... then Anastasia heard a loud noise, breaking her happy reverie.

What was that? A scream? Yes, it was. But where? She ran down the street, and came upon a house. A flaming house. With a little boy trapped inside. Anastasia had never been a person who waited around for others. Or for anything, really. She raced inside the house, and found the sobbing little boy on the first floor. she tossed him out the window, where he landed in a pile of snow, and made her way back to the door. "Almost there, almost there... AAH!" Anastasia tripped on a board, and fell into the flames. "NOO! I can't die! I'm only 13!" She yelled, but then realized something. She was in no pain, and was...floating?!! What was this?!
I'll make a Chapter 2 soon--Emerald

Chapter 2:
Shocked, Anastasia looked around. All she could see was red flames, everywhere. Then she looked at her hands, and got the suprise of her life: She was on fire. Not like the kind where you did something awesome, Anastasia was a living, breathing, thinking, fireball. Anastasia reacted as a normal, rational human being would. "WHAT THE!? AAAAAHHHHHHHHH!". This was NOT cool. "Hey, what was that?" She pointed towards a rustling sound. "Did you do this to me?!". More sounds. "Hey, get back here!" she pointed again and a small ball of flames shot out. "Ouchie! What was that for?" "Mikey! shhhhh!" "But it hurt!" More rustling around. "Are you okay?" Anastasia walked, er, flew towards the male voice. Then she saw a green face with a bright orange mask around it. What the heck? "Um hello, fire lady? Are you okay?" 3 more green faces came into sight. Anastasia fainted.

A little while later, Anastasia woke up, in a strange, slimy place. Where was she? and.. what was that horrendous smell? "Let's go check on her!" That voice again. Did they kidnap her? "No, Mikey" "But Donnie.." Hmm. They had human names, at least. "We can at least check, Donnie" Oh no, they were coming back! "Okay, Leo" Anastasia braced herself. 3 Green umm.. uh.. somethings walked into the room. Orange said "Yay you're awake! I'm Mikey! And your name should be.. hmmm.. Lemme think.. I got it! Flame!"
"My name is Anastasia, but who and what are you?" she replied.

There will be a Chapter 3 soon, this one just started getting kinda long. Hopefully there will be only 3-4 chapters.

"I'm Mikey!" The orange masked thing answered. "And these two are Donnie," He pointed towards purple " And-" "And why should we tell her this?" Blue interrupted. MIkey said, "Uhhhhhhhhh............" unsure how to respond. All three went into one corner, whispering. Anastasia tried frantically to hear what they said, but only heard a snippet here and there, until she heard Donnie say something shocking: "Well, she's a mutant too".
A mutant? How?
They returned to her bed, seeming to have made a decision. "What happened to me?!" She demanded. Donnie sighed, and the the other two seemed grim. Well, Mikey seemed as grim as he could possibly be, which wasn't saying much. "Okay, so there is a special liquid called Mutagen-" Donnie started off. " And it will, ahem, mutate whomever it touches into whatever natural object or animal they last touched or are currently touching. I'm still working out the details of how it works, but you get the gist of it." Anastasia nodded.

" And well, some fell on you right as you fell into that fire, quite a miracle. It saved your life." He finished.
"WAIT! Am I still on fire?!" Anastasia screeched in a panic. Mikey answered "No, when you passed out you stopped. You looked so cool though! And my arm stopped hurting, so that's good, right?" Anastasia cried "NO! Not cool! Not 'good' at all! What do I do now? Right when my life was starting to look up, this happens! ARGH!" "Umm... Miss?" Blue said, looking a liitle scared. "What? Some other terrible thing?" She yelled, then Donnie slowly pointed towards her hair. Anastasia looked around the room for a mirror, and was suprised by the taste in it. While it wasn't girly, it was quite obviously intended for a girl. How could giant green boys with only three fingers per hand do this? Aha! a mirror lay in the back wall of the wardrobe, which was filled with a suprising amount of yellow clothes.

Anastasia was shocked to see the image before her. Her hair had become a giant mass of flames, her eyes were a glowing white all over, and her clothes were replaced by fire, her skin literally burning. How on earth would she explain this at school? "How does she do that?" Mikey asked, seeming to have gotten over some of his fear. "Well, it happened when she got upset, maybe there is a connection.." Donnie said, and ran off. " Oka- Hey where are you going?!" "i'm gonna grab some test stuff. Try and calm her down, Leo" Donnie yelled back. "All right, think of calm thoughts Annie-" "It's Anastasia" "Okay, think of things that make you happy Anastasia, like puppies." "And pizza!" Mikey added.

Okay, calm down Anastasia, it's all right. Everything will be fine. Puppies and pizza, puppies and pizza, she thought. The flames slowly went away, and her eyes returned to their normal, bright green colour.

Ok, that was chapter 3. and yes, it's verry long. I will do my very best to have it done in 4 chapters, and when I am done, I'll put up a character description.

Chapter 4:
Leo took a cautious step towards Anastasia, Mikey still by the door, seeming too scared to come near. And who could blame him? Anastasia wouldn't want to get close to a girl that became a ball of flames at random either. "Uhhh... Are you all done?" Leo asked putting a three-fingered hand on her shoulder. Before she could respond, Donnie barreled into the room with a giant box of who-knows-what. "So the Wherzit connects to the Whatzit, and this goes here.... And that goes there... Will you hold out your arm please?" Anastasia noticed one arm had a small Band-Aid on it. "Why is this here?" She asked, pointing. Donnie took a break from arranging everything to look up and say " Well, I kinda needed to get a blood sample, to make sure you were okay." Anastasia would have done the fire thing again, but she was too exhausted both mentally and physically to be really upset. "So you just did that without my permission?" "Errr, sorry. Do I have your permission now?" He said, seeming sincere.

"Tell me one good reason I should trust a giant turtle that I've known for 15 minutes to be my doctor." She demanded, desperately trying to regain control of the beyond insane situation. The three turtles looked at her for a moment, and Donnie started to say something but Leo interupted. "You're right." He said simply. "I know my rights, and, wait what?" Anastasia looked in suprise at Leo. "You are too tired to deal with this stuff right now. How about you stay the last few hours of tonight and we will do all the sciencey stuff in the morning. And then, tomorow night, We will take you back to where ever you live. Can you tell your family you spent the night at a friends house?" Anastasia took a deep breath in before answering "Don't have a family. Or friends."

I'm so sorry, but this is starting to become a book almost! AGH! I just got too inspired... Looking at you Sparki Wolf and Jordan5432. Anyway, next chapter I hope to have her meet the Mutanimals.

VERY IMPORTANT AUTHOR'S NOTE:
This story has become discontinued. Believe me, I've been trying to write a new chapter for months and have been unable to come up with anything at all. Just dead end after dead end. What I want refuses to work out for me. However, all my exercises (and one very awesome English teacher) have really improved my writing skills,( if one could say I have any) and I have decided on trying something different.
I finally decided that Anastasia will not remain in the TMNT fandom. After much thought, it is clear to me that she will fit better in a different world; the Percy Jackson series, something I re-discovered a month or two ago. (Hoping the house ban on buying non-school books lifts this summer and I can get started on reading Heroes of Olympus.) I will start writing a new backstory for Anastasia Marie Smith, featuring all our favorite demigods. Maybe.
This story has now become non-canonical and basically useless, but some people liked my scribbling, so I will leave this up, maybe going through every now and again to clear things up and edit. :)

~Emerald