After a routine rescue mission ends in tragedy, young apprentice bounty hunter Iria returns to her homeworld with a deadly secret: the Zeiram, a deadly, seemingly indestructible alien life form, is on the loose and headed for the unsuspecting planet. This knowledge makes Iria the target of assasins from the Tedan Tippedai Corporation, who wish to harness the destructive power of the Zeiram as a bio-weapon.  Intent on exposing the Corporation’s sinister plot and avenging the death of her brother & mentor Gren – who was slaughtered before her eyes at the hands of the Zeiram – Iria and her ragtag crew must hunt down the alien juggernaut and uncover the truth.