When Shredder schemes to create a fearsome army of mutants, the Turtles have no choice but to rely on the help of the newest recruit to the Foot Clan: The Pulverizer!
After Leonardo, Raphael, and Donatello fall under the control of a parasitic Wasp, Michelangelo must fight his brothers to save them.
Donatello breaks into a secret Kraang detention center in order to rescue Kirby O'Neil. But when he discovers they are trapped inside with a deadly mutant prisoner, he realizes that breaking in was the easy part.
As the Turtles make a desperate assault on TCRI to shut down an alien portal, they find themselves engaging in the most difficult battle yet.
When Shredder teams with the Kraang to receive a batch of mutagen, the Turtles' problems only get worse—even putting their friendship with April at stake.
When the Turtles face Shredder's newest threat, an army of Robot Foot Soldiers, Karai captures Leonardo and forces him to do battle with these new and improved ninjas that can adapt to his every move.
While tracking mutagen, the Turtles bring a mutated squirrel back to the lair. When it starts multiplying, the Turtles must hunt the squirrel mutants and prevent them escaping into the city.
Donatello obsessively experiments with mutagen in a bid to find a cure for April's mutated father. Unfortunately this puts April in danger from a new threat—Mutagen Man!
Michelangelo is tired of being the "runt of the litter." But when he fools around with some mutagen, he gets a dangerous infection that is mutating out of control.
April tries to resume a normal teenage life, but when Karai starts hunting her again, April realizes she may have put her new friend Casey Jones in danger as well.
Greg Cipes
Michelangelo / "Mikey
Seth Green
Leonardo / "Leo"
Sean Astin
Raphael / "Raph"
Rob Paulsen
Donatello / "Don" or "Donnie"
Mae Whitman
April O'Neil