Sent from the future to save mankind from a nightmarish holocaust, three young men must blend into present-day society and uncover the dangerous machinations of a group of sinister scientists. Unfortunately for Kouji, Ryou and Gawl, their apparent youth leaves them with no option but to pretend to be foreign exchange students at the local high school. Their cover almost immediately begins to wear thin when the daughter of the boarding house where they are staying begins to suspect Gawl of being up to no good. In truth, Gawl is the ultimate weapon against evil, a bio-enhanced generator capable of transforming into an awesome inhuman form of unbelievable power. However, even Gawl's incredible abilities may not be enough, for the scientists have their own army of monstrous generators!