Since he was a child, Keisuke has always had an uncomfortable problem of accidentally touching girls in inappropriate places at the worst possible moments. However, things take a surreal turn when an angelic figure named Ririi and her fairy companion, Chappi, appear before him. Ririi reveals that Keisuke is actually a legendary hero and that the incidents were a result of his suppressed power in his lower region.
Upon learning this shocking truth, Keisuke begins to feel revitalized as a massive black gun barrel emerges from his crotch. This gun is none other than the revered Zetsurin Buster, also known as the holy genital gun.
