In the woods, Shou and his companion Tetsurou make a chance discovery of a peculiar orb-shaped contraption called the Guyver Unit. The gadget melds with Shou's physical being and transforms him into an extraterrestrial warrior, Guyver. His chief responsibility is to defend the Guyver Unit from Chronos, a Japanese conglomerate obsessively pursuing it and two other identical units. To accomplish this task, Chronos unleashes ferocious beasts named Zoanoids. As a result, Shou's life and very essence become imperiled.