Invader Zim, banished from his home planet, comes to Earth, and sets up a base to begin learning about its inhabitants, but Dib is on his tail.

In order to prove his humanity, Zim befriends a weird kid named Keef who won't go away. Zim and Dib fight a microscopic war with Dib's internal organs as the battle field.

In order to prove that he's human, Zim brings his Robo-parents to school with disastrous results. Zim and Gir get lost in the city.

Zim, equipped with special germ-seeing goggles, becomes obsessed with cleanliness. Convinced that a doctor's examination will reveal that he is not human, Zim harvests the children's organs and stuffs them into his own body.

Zim finds himself among a group of alien-worshipping weirdos and must get away. Zim and Dib engage in a water fight to end all water fights.

Zim and Dib take tests to determine their careers and spend the day with their adult counterparts. In order to attend a meeting of the Swollen Eyeball Network, Dib must obtain a signature from the ever-elusive Professor Membrane.