Donatello had always been the smartest of his family, especially his siblings. He was only two years old when it happened. He had been out with his mother taking, care of the shopping. His siblings were with his father. He was the fourth of a set of five children born on the same day. He had held onto his mother's hand tightly as she went through the store, looking for groceries. The family had recently moved to America after having a falling out with another competitor for the mother's heart. Teng Shen was a woman of great beauty and kindness. Oroku Saki and Hamato Yoshi both competed for the heart of Teng Shen, but only one had won with his own kindness. Oroku Saki was completely jealous, and had become even more so when he had found out about their quintuplets; Miwa, Leonardo, Raphael, Donatello, and Michelangelo. Hamato Yoshi took his family to the city of New York in America to live and hide from his enemy.
Unfortunately, they were followed. Teng Shen was now running in the sewers, clutching her baby to her chest as she was followed. Donatello had fear in his mahogany eyes as he clutched his mother's kimono. "Mother… they're coming." Donatello was the genius of the five and could already talk. He was also already getting his hands on tools and trying to figure out how things worked. His curiosity was something that had always pleased his parents, as it was tempered with patience.
"I know, Donatello. Just hold on." Tears were falling from her face as she ran through the sewers, trying to lose the ninjas that followed her. "Gah!" She tripped upon a few animals that had somehow gotten into the sewers, accidently releasing her son from her grasp. "Donatello!" She had tripped on a rat and scrambled to get closer to her baby to protect him, as he had landed on some sort of turtle that had been flushed down the sewers for some reason.
"MOMMY!" The toddler cried as the ninja came closer. One of the newer and younger ninja had accidently thrown a vial of mutagen they were supposed to deliver instead of a smoke pellet. The two were covered in the mutagen as Teng Shen grabbed her son and continued running, ignoring the pains of the mutagen running through her system now. She had to get her baby to safety. They had only been slightly splashed with the mutagen, but Donatello could already feel himself changing because of the turtle he had fallen near and the mutagen. He held on tighter as the pain became almost unbearable for the child.
Teng Shen found herself moving faster than ever before because of her own mutation. Her rat legs were stronger and she found her tail was attacking anyone that came too close. She cried as she found her son had turned into a turtle, but that he was still sentient. She then looked at her own paws while running and was scared. She couldn't go back to her family, not like this at least.
Eventually the two had lost their pursuers. They found themselves in a small old abandoned subway station. Teng Shen hid in one of the subway cars, having closed the doors behind her, and cried with her little baby turtle in her arms. The little turtle, though a genius, didn't understand why she was crying. They were safe now. Then he took stock of what had happened to them. He had a shell, and she had a tail. He gasped. They couldn't go home like this! They'd scare his siblings most likely. Donatello started to sniffle as his mind connected the dots. He then looked to his mother. "We're gonna be alright, mother." Donatello said as he patted her hand. She looked him square in the eyes and noticed his determination. "We'll stay here until I can fix us. I'll fix us, I promise." Donatello was always trying to fix people's problems, especially among his siblings, though they were only toddlers.
Teng Shen hugged her son tighter and whispered into his ear. "My son, you'd promise me the moon if you thought it would make me feel better."
"I can make a moon!" The boy said innocently as he hugged her back. "Do you want a moon?"
"No thank you, baby. I want to go home… but we can't like this…"
Donatello looked at his strange hands, as they now only had three fingers. He grinned with a smile that had a gap in the teeth. "I got three fingers!" His exclamation was filled with laughter, making his mother chuckle weakly.
"Yes… and I have a tail…"