Every 3,000 years the Overfiend awakens to reunite the three realms -- demons, humans, and man-beasts. Prior to awakening the Overfiend resides in a human body, with human limitations and quite oblivious to his true nature. Man-beast Amano Jyaku and his sister Megumi have been searching for the Overfiend for a long time and they finally found him in the person of 19-year old loser / lecher / masturbator extraordinare Tatsuo Nagumo. Tatsuo has no idea he is the Overfiend, all he knows is that he fancies the sexy cheerleader Akemi and likes to stimulate himself while peeking at her in the locker room. Demons are also searching for the Overfiend, unfortunately when they provoke Tatsuo too far all hell breaks loose...