Makenko was once an ordinary boy—until Dr. Mud, a brain monster, kidnapped him and turned him into a cyborg with the power to destroy both the monster and human worlds! While seeking revenge, he is accidentally accompanied by Makendo, a monster hunter who would rather not be one, and her younger sister Hikari, who couldn't be happier about it. The trio battles evil demons and quirky monsters to defeat the villains and restore Makenko's original body!