OH. SO WHAT WOULD HAVE HAPPENED?
As with most TV shows, production schedules and script re-writes often determine what stories do and don't make it on air. One prime of example of this took place during the production of Season Five of Turtles 2K3 when the episode Nightmares Recycled failed to make it to air.
Originally intended to be the 110th episode of the show's run, Nightmares Recycled would have seen Raphael, Donatello, Casey Jones and April O'Neil face-off with returning villain's Garbageman and Hun. However, the Turtles' encounter with the villains would have been overshadowed by the revelation that Hun and Garbageman were actually brothers who had been surgically separated as kids!
BUT WHAT DID HAPPEN?
A script for the episode was written and some production work took place, but before the episode could be completed 4Kids - the co-producers of the show - decided that the story was inappropriate to air.
The script explained that Hun and Garbageman were separated when they were youngsters, with Garbageman being discarded like trash by a back-street surgeon. Understandably this was not a subject that would fit comfortably within the confines of an animated series aimed at kids, and it certainly wouldn't have been screened by an American TV network.
OH. WHAT ELSE WAS SET TO HAPPEN?
In addition to an extra episode in Season Five, there were also plans to produce an eighth season of the series, subtitled The Shredder Wars. The season would have picked up on events depicted in the Season Seven episode Tempus Fugit which saw different versions of Shredder at war with each other.