The Turtles and April are watching a news report that is bashing the Turtles' reputation. They are annoyed by it, and decide that they need to get rid of the Shredder. In order to keep communications high, Donatello gives April a Turtle Comm. Shredder appears on the Turtles' TV and tells them of his RetroMutagen Ray, which has the power to undo mutations. Shredder tells them that if they want Hamato Yoshi back, they can come and get it. Splinter knows that it's a trap, since that if the Turtles were hit with it, it would be back to the pet shop for them.
So the five of them go topside and commandeer the StarMobile the Neutrinos left behind. However, it is low on fuel, and it takes very rare plutonium. Donatello decides to go to Baxter's lab to find a better weapon. Bebop and Rocksteady ambush the Turtles, and through a very interesting a grueling battle, they pound them into cement... litteraly.
Meanwhile, at the Technodrome, Shredder activates Krang's robot body, and he is interrupted by the Turtles. He sends a Foot Soldier squadron to stop them, and Splinter goes inside the Technodrome to fight Shredder while the Turtles "break some foot." The Turtles get inside the Technodrome, only to be chased by Krang, who has a chip in his body that can enlarge him. Krang punches a hole in the street above them, and begins an assault. Splinter is clashing a battle with Shredder over the ray.
April gets a news crew to tape the fight between Krang and the Turtles, and Donatello arrives with the Turtle Blimp. Raphael and Michelangelo stall him while Leonardo and Donatello are able to destroy the chip. When Krang shrinks, he contacts Shredder for help. Shredder traps Splinter in a force field and takes the Ray to demutate the Turtles. He breaks out and stops Shredder just in time. Shredder and Krang escape to the Technodrome to bring the Foot Soldiers to Earth. The Turtles sneak in and Donatello reverses the portal mechanism so the Technodrome is sucked into Dimension X. The Shredder has offically been shredded.