A/N: Ok. This is my first ever TMNT fic. I'm gonna have fun with this. There's gonna be a character that I add. You'll see that the story easily matches the title. The new character will be a girl, and when the turtles meet her, they are five years old and she is three. You guys will LOVE this!

Disclaimer: I don't own the Turtles or anything else from the cartoon. I only own Casey AKA: Starlight Ninja. If you steal her, then prepare to die.

Summary: She was running through the sewers, the man who killed her mother and father hot on her trail. Then she collapsed from exhaustion, and they found her.

Growing Up With the Turtles.

Part 1: Casey meets the turtles

Casey woke up that night to a sound coming from the living room. She climbed out of her bed and grabbed her flashlight. She had a natural sense of stealth, so she walked to the living room undetected. Peeking around the doorway, she held back a scream. Her parents were on the floor, dead. She saw the killer taking anything valuable from the room. Knowing she had to get out of the house, Casey silently ran to her room and grabbed the biggest backpack she could find. She quickly shoved all the clothes and belongings she could in it. Her bedroom was one the ground floor. She could easily jump out the window and not get hurt.

Before jumping out the window, Casey picked up the gold locket from her desk and put it on. She also quickly grabbed a large cloth bag with all her favorite chapter books in it, her notebooks, which had her drawings and stories in them, and her pencils. Then she turned to the window, which was beside the door.

She stopped dead in her tracks. The killer was standing in the doorway. Lucky for Casey, there was another window not even a foot behind her...and, it was already open.

Casey turned around and jumped out the window, the killer hot on her trail. Running down an alley, she realized she had reached a dead end! Her only escape was an open manhole. Casey quickly jumped in, cloth bag, notebooks, and pencils still in hand.

Landing with a splash, Casey took off, running as fast as her small legs would carry her. The man was not far behind her. She shrieked as gunshots were heard and bullets whizzed past her head, never slowing her pace. She heard a noise come from a tunnel to her right. Casey ran down the tunnel, pushing herself to the limit, ignoring the stitch in her side.

She ran for ten minutes straight before she tripped, clutching her side. She heard voices from farther down the tunnel.

"COWABUNGA!" yelled the voice.

Casey followed her first instinct and screamed at the top of her lungs.

"Somebody, please, HELP ME!" she shrieked.

She was now lying on her back, watching helplessly as the murderer slowly came forward. Casey squeezed her eyes shut and screamed as loud as her three-year-old lungs would allow. She didn't dare open her eyes, but she heard something run past her and what sounded like something fighting the man, then something ran away. Casey didn't open her eyes until she felt a hand on her shoulder.

Slowly opening her eyes and looking up, Casey sees what looks like a giant turtle kneeling in front of her. It was wearing a blue bandana that doubled as a mask. Casey was surprised, but she wasn't scared. They were not much bigger than her, and Casey felt as though she could trust this creature.

"I'm Leonardo. Are you alright?" asked the strange creature. From his voice, Casey could tell that this turtle-thing was male.

"Yeah. At least, I think so. I'm Casey," she said, getting over the surprise that she was talking to a turtle that was almost a foot taller than her. Suddenly, her eyes filled with tears as the realization that her parents had been killed washed over her.

Leonardo looked at Casey, wondering why her eyes had suddenly filled with tears. His brothers were standing behind him. Casey hadn't noticed them yet. She looked up at the three other turtles standing behind Leonardo. They, like him, were wearing headband/masks, but were different colors. One was wearing a purple one, another, who looked ticked off, was wearing a red one, and the last was wearing an orange headband.

"Who're they?" asked the three-year-old cautiously.

"They're my brothers. That's Michelangelo," he pointed at the orange-clad turtle. "Donatello," the purple-clad turtle. "And Raphael," the red-clad turtle.

Casey immediately looked at the ground upon hearing the word 'brothers'. It reminded her that her family was now dead. She hugged her knees and started crying. Donatello, Michelangelo, and Raphael walked over and stood around her. Leonardo looked to his brothers.

"Go get Master Splinter. I'll stay with her," he said. His brothers were hesitant about leaving, but obeyed their eldest sibling. Once they began walking away, Leonardo turned his attention back to Casey. He noticed that she was holding something in her arms, hugging it.

"What's wrong?" he finally asked. The three-year-old looked up at him.

"My parents are...dead," she whispered. Leonardo was surprised a little when Casey suddenly moved forward and hugged him, sobbing into his shoulder. Recovering from his surprised state, Leonardo held the three-year-old in a brotherly fashion, comforting the sobbing girl. He didn't look up until he heard his brothers and Sensei walking towards him. Leonardo looked at the small girl who had cried herself to sleep and noticed that what she had been hugging earlier was an old, tattered stuffed cat.

Leonardo watched as the small girl was lifted by his sensei and cradled in his father-figure's arms. Casey snuggled into Splinter's gentle grasp. Splinter looked at Leonardo and asked the question which was all too obvious that he would ask.

"Was she frightened of you?" Splinter asked Leonardo.

"No. She actually seemed to relax upon seeing us," he answered. His sensei looked quite surprised, but led his sons back to their home.