Once an ordinary boy, Makenko's life takes a drastic turn when he is abducted by the malevolent Dr. Mud and altered into a powerful cyborg, destined to save both the human and monster realms from destruction. Along his journey of retribution, he finds himself accompanied by Makendo, a reluctant monster hunter, and her eager sister Hikari. Battling sinister demons and eccentric monsters, the trio embarks on a mission to defeat evil forces, reclaim Makenko's physical form, and restore balance to the worlds.