A horrible toxic accident transforms downtrodden janitor Winston Gooze into a new evolution of hero: The Toxic Avenger. Now wielding a glowing mop with super-human strength, he must race against time to save his son and stop a ruthless and power-hungry tyrant bent on harnessing toxic superpowers to strengthen his polluted empire.

A gang of thugs devise a cruel hoax that goes horribly wrong as Melvin, a nerdy emaciated janitor at the local health club, is cast through a third story window into a vat of hazardous toxic waste.