The animated series follows earnest but inept alien Zim, who is assigned to facilitate conquering Earth for the Irken Armada. In reality, his superiors want rid of him, and send him off with a malfunctioning robot assistant, Gir, hoping he never returns. Zim runs afoul of young paranormal investigator Dib on Earth, and hilariously surreal adventures ensue.

Nickelodeon plans a 90-minute movie, which will see original series voice actors Richard Horvitz (Zim), Rikki Simons (GIR), Andy Berman (Dib), and Melissa Fahn (Gaz) return. The movie picks up the plot with a “perpetually desperate and delusional” Zim attempting a new plot to achieve his goals.

The delightfully bizarre Invader Zim debuted on Nickelodeon in 2001, created by comic writer Jhonen Vasquez (Johnny the Homicidal Maniac, Squee!, I Feel Sick). Though the show was critically acclaimed, and animator Kyle Menke won an Emmy for Outstanding Individual Achievement in Animation for his storyboarding on “The Nightmare Begins, ” the network cancelled the show halfway through the second season since ratings were low in the target demographic (see "'Invader Zim' Repelled").

Oni launched an Invader Zim comic series in 2015 (see “'Invader Zim' Comics”).