The Ninja Turtles (Leonardo, Raphael, Michelangelo, and Donatello) are on a mission to retrieve the Life Transformer Gun from Shredder, a device that could restore their sensei Splinter back to his human form. The Turtles' first objective is to rescue their reporter friend April O'Neil, who is being held captive by Bebop and Rocksteady somewhere in the city. After rescuing April, the turtles must swim underwater to disarm a series of bombs set to destroy a dam, rescue Splinter from the Mecha Turtle, destroy a giant Mouser, find the Technodrome and eventually defeat Shredder.