Invader Dib was supposedly to be the three-part series finale/TV movie that was to wrap the series up. However, since the show was abruptly cancelled during the beginning of the second season, it was never finished or aired. The general plot would have followed Tenn's kidnapping by the Meekrob, and an all-out war happening between them and the Irkens.
It is important to note that at the time of cancellation, ideas for this episode were very sketchy and undecided upon, and plot details may be inaccurate.
As only vague ideas were ever discussed, with nothing really agreed on, there is no definite plot for this episode/movie. The only things that were certain was that Dib would travel to Irk (likely in Tak's Ship) and attempt to take over or destroy the Irken race, with Zim desperately trying to stop him. Dib most likely would have had help from various sources, as according to other ideas that were tossed around for the untitled Season 2 finale, Dib would have been named the Ambassador to Meekrob, and The Resisty would have been revealed to be in league with the Meekrob themselves. Zim likely would have had the backup of all his Irken "allies", and possibly even Gaz. Zim and Skoodge allegedly rescue Invader Tenn, although Zim is left behind and is knocked unconscious, followed by a vision of all Irken life dying. He awakes to see a hooded figure who tells him to fight, and somehow wins the war.
It is completely unclear as to whether Zim or Dib would have come out on top in the ending in the final version. Some fans believe that Dib would have ended up winning, overthrowing the Irken race; however, given that Jhonen Vasquez wanted Dib to end up on Saturn, it's unlikely that he would have won in the final version. Though there is the possibility, perhaps, that while Dib himself was totally unsuccessful, any allies he might have had at the time could still prevail. Another idea that is suggested was that Dib would ultimately lose and become "horribly scarred", and become a test subject for Irken military weaponry (or sent to an Irken psychiatric facility), with Zim becoming the Tallest (or in his case, the Almighty Smallest). Interestingly enough, Dib may have inadvertently won in the end, as the Irkens would possibly be in for a horrible fate with Zim as their leader, or perhaps not.
Jhonen claimed to have planned for Zim to begin to see a sublime beauty in life on Earth and thus lose the desire to destroy the planet. Additionally, Vasquez brought up the idea of Zim becoming a kind of legal guardian of Earth, similar to The Marvel character Daredevil. He wanted to convey this in a way that would move the audience to tears. However, it may (or may not) have been a joke. Also, Eric Trueheart had brought up the idea of Gaz becoming Zim's consort after moving to Irk with him and deposing the Tallest, which deviantART user TheRealRNO seems to confirm.
- When Dib goes out to destroy the Irken race, it is like how Zim has tried to destroy the human race time and time again.
- One of the plots discussed behind closed doors would have had Zim and Gaz (cloaked in a hood to hide her identity) teaming up to put an end to the carnage and being crowned Irk's new rulers soon after, banishing Dib, Tak and their forces to planet Saturn and deposing the previous Tallest, Almighty Tallest Red and Almighty Tallest Purple, from the throne. As Zim would spare Earth from the Irkens' wrath, realizing its beauty, he would most likely have made all the other conquered planets go free as well, including Smikka's, in a domino effect.