Frustrated at Baxter's latest failure, Shredder contacts Krang in Dimension X and demands that Rocksteady and Bebop be sent to aid him.

Sensing Master Splinter's despair at his new life as a rat, the Turtles agree to use the small amount of mutagen that they have left to concoct a formula that will revert Splinter back into Yoshi.

Shredder and Krang produce hi-tech versions of Rocksteady and Bebop to keep the Turtles busy.