The Teenage Mutant Ninja Turtles meet.the Teenage Mutant Ninja Turtles? What the shell is going on? An out-of-the-ordinary encounter with the strange alien ooze mutates four ordinary pet turtles - Leonardo, Raphael, Michelangelo, and Donatello - into talking, walking, fighting green machines! Together, these brothers train with the legendary sensei rat, Splinter, to master the martial art of Ninjitsu. In this truly turtle-powered tale, the turtles from one dimension meet the turtles from another dimension when a teleporting mishap occurs. What the shell is going on? Together, the turtles must locate the Technodrome to fix this mess! Meanwhile, Shredder tracks down his counterpart, Ch'rell, who devises a master plan to travel back to the Prime Universe to get rid of the turtles once and for all! As worlds collide, the turtles come face to face with the classic characters like Splinter, Casey, and April, and a slew of archenemies including Krang, Hun, the Foot Soldiers, the Purple Dragons, Bebop and Rocksteady!