On one normal night in New York city, 4 fully grown Mutant Turtles do their evening training with Master Splinter at their Sewer Den below New York. They've spent their 15 years with their sensei, Master Splinter and learning the arts of Ninjitsu. They've never reveal themselves to the outside world, due to their appearances. As it would lead them to trouble. But when all seems fair a pack of rubble eating tiny machines came into their Den and start chewing up the place. They battled these machines one by one with their Ninja skills. Unfortinately their den starts to collapse and they're'e now separated from their master. They contacted him by their own cell phones "Shell Cell" and they agree to meet up with him around the other side. But the way to the other side is blocked. So they'll have to go "top side" in other to get to the other side. And this will lead to battling one of New york's toughest gangs "The Purple Dragons".

When April O'Neil wakes up in the Turtle's lair she has major trouble dealing with the reality of four giant talking Turtles and a Zen-master rat. She soon learns of the origin of the Teenage Mutant Ninja Turtles and they realize their common enemy is Baxter Stockman and his army of robotic Mousers.