[neatoman]

Well, there are two endings to the show. The official ending that aired last and Nickelodeon is officially declaring to be the ending, and the last produced episodes who the showrunner wants to be considered the ending.

1. FW Shredder and Krang show with the Technodrome but leave Bebop and Rocksteady, because they don't really think they need them. They hire Nick Bebop and Rocksteady, who are out of a job since Shredder died. The FW Turtles show up, tell the Nick Turtles what's up (who agree to help them, mostly because they've got nothing else to do). Bebop and Rocksteady question wheter or not it's a good idea to work for crazy morons while the Turtles try to stop them. Shredder and Krang reveal that they intend to use the Technodrome to destroy the world, so Bebop and Rocksteady destroy it, redeeming them in the eyes of the Turtles. The FW characters goes home and we're given a bizarre music video.

2. It's an apocalyptic future. Raph is old has a bad memory, he travels around with Don in a robotic body. Everything has been nuked to hell and the only ones alive are mutants. The Turtles themselves, ICK and Chompy are seemingly the only characters who survived. Raph and Don meet a girl with a map to an oasis only Mikey can read. On their way to Mikey they're attacked by badgers and lizards, who Raph beats and becomes the new leader of. THe former leader of the badgers seek help from evil Leo to reclaim his position. Raph knocks some sense into Leo and they all go to the oasis.

Take your pick, a hollow attempt to recreate Turtles Forever or the one that barely connects to anything.