Somewhere in deep space the starship Karma has been hijacked- with the vice president of The Tedan Tippedai Corporation and a mysterious cargo on board. Iria, an apprentice bounty hunter, accompanies her brother Gren, and his boss Bob on a rescue mission before the authorities arrive. The extraction turns deadly when it is revealed that the cargo is Zeiram. The Tedan Tippedai Corporation secretly attempted to import the monster to be developed into a powerful, new bio-weapon.

Escaping From the exploding starship, Iria lands on the planet Taowajan-the fate of Gren and Bob are still uncertain- and must find her way home. However, Zeiram was not destroyed in the explosion, and crashes into the citie's slums- where he begins a program of "urban renewal". As the authorities turn a blind eye, only Iria, and her street wise sidekicks, Kei and Komemasa, can halt his rampage. But who is the mysterious voice over Iria's commicator?...........