
Cowabunga, dude! The Turtles are back. Leonardo, Donatello, Raphael and Michelangelo are four mutant turtles, trained in the art of "ninjutsu" by their sensei, Master Splinter. The animated series explores their camaraderie as they learn to rely on one another as they unravel the mystery of their existence and train to become the heroes they are destined to be. And they're doing all that while trying to defeat Master Shredder, an old enemy of Splinter who is training a peculiar band of ninjas while hiding in New York City. When they are in the surface world, the Turtles become involved in a conspiracy involving alien creatures, robotic droids and missing scientists. And they come face to face with the glowing green substance that originally mutated them.

When Casey and Donatello bond while building Casey's new hot rod, the bond is challenged by a hot-rodding mutant.

When Casey, Raph, Mikey and Donnie are captured by a new mutant, April and Leo must overcome disabilities in order to save them.

Leo takes the Turtles to train in the woods in an advanced ninja ritual; the Turtles must overcome their weaknesses and face their enemies to become a true ninja.

When the Turtles return to the city to search for Splinter, they discover that the city has been overrun with Kraang.