The series centers on an alien named Zim from the planet Irk, who attempts to conquer a dark and satirical parody of Earth. The plot harshly mocks many institutions of American public life, such as public holidays, national security, and the education system. Zim is a member of the Irkinsky army, a failure with delusions of grandeur. His constant attempts to conquer Earth or destroy humanity always end in failure. Zim has to constantly disguise himself using contact lenses and a wig, explaining his green skin color and lack of ears as a skin disease; the Earthlings, who are not distinguished by intelligence, believe him.