Zim is a member of the mighty Irken race, a species of alien life forms whose social hierarchy is based on height. The Irken leaders are the Almighty Tallest (Red and purple) Zim was banished to the planet Foodcourtia as a food slave for killing all the other Invaders during Operation Impending Doom 1 and completely destroying their home planet Irk I.[4]
Upon hearing of Operation Impending Doom II, Zim "quits" being banished and arrives at the Great Assigning where Irken soldiers are chosen to become Invaders and given helper robots ( and treated to nachos), special soldiers whose mission it is to blend in with the indigenous life forms of their assigned planet and collect intelligence before leading them to their doom. Zim pleads with the Tallest to assign him a planet, and in a desperate act to get Zim as far away as possible(so he dosen't ruin it again), they assign him to a "Mystery Planet" on the outskirts of their known universe (and give him a faulty robot mad from spare pieces that has candy for brains), which turns out to be Earth.
The show features Zim trying to conquer the Earth while his ( big-headed and paranormal obsessed) human arch-nemesis Dib tries to stop him. Technically, the show takes place in a world of its own, with a present-day Earth more technologically advanced than ours. Because the alternate universe aspect was never emphasized, the result is that the series appears to be set at some point in the near future. And running about three seasons, which you can see on nicktoons network, or get on DvD.
