Zim is an alien from the planet Irken, where status is determined by how tall one is. Since Zim is one of the shortest people on Irken (and incompetent to boot), the Almighty Tallest send him on a fake mission by the deranged robot GIR, Zim disguises himself as an ordinary schoolboy in order to gather information about Earth. Only Dib, a pre-teen Mulder wannabee, realizes that Zim is an alien.