When a battle between the Purple Dragons and what appear to be the Teenage Mutant Ninja Turtles is captured on film, the Turtles are quick to refute their master Splinter’s accusations of carelessness. Breaking into the Purple Dragons’ headquarters to get to the bottom of these mysterious dopplegangers, our Turtles discover that their “impostors” are, in fact, versions of them from another dimension. The goofy otherdimensional “1987 Turtles” prove to be a hassle for the more serious-minded “2003 Turtles”, but they are soon able to discern that they were teleported into their world in a dimensional portal accident that has also brought their arch-enemies, Shredder and Krang, and their battle fortress, the Technodrome, along with them.

The eight Turtles head below the ground to track down the Technodrome, but their presence together only clues Shredder in to the fact that there may be a version of himself on this world that he can ally with to take the Turtles down. The Technodrome escapes, and the Turtles resolve to create a portal device of their own so they can travel to the “1987 universe” and obtain the gear the 1987 Turtles usually use to take the Technodrome down. While the Turtles are occupied with this task, Shredder uses the Technodrome’s technology to locate his dimensional counterpart, the Utrom known as Ch’rell, still in frozen exile on an ice asteroid after his final defeat by the 2003 Turtles. Ch’rell is teleported to the Technodrome, but upon recovering, immediately overthrows his bumbling other-self and seizes control of the fortress with the aid of his adopted daughter, Karai…