When the notorious Diaper Mafia take hostage the Tromaville School for the Very Special, only the Toxic Avenger and his morbidly obese sidekick Lardass can save Tromaville.

Toxie finds he has nothing to do as a superhero, as he has ridden his city of evil. So he decides to go to work for a major corporation, which he discovers may be the evilest of all his adversaries.

The Toxic Avenger is lured to Tokyo, Japan by the evil corporation Apocalypse Inc. So while the Toxic Avenger is fighting crime in Tokyo, Apocalypse Inc. spread evil in Tromaville.