The story follows the exploits of the protagonists—man-beast Jyaku Amano, his nymphomaniac sister Megumi and their companion Kuroko—as their 300-year search for the Overfiend takes them to a high school in Osaka, Japan. Their discoveries led them to two students: shy, lecherous Tatsuo Nagumo and school idol Akemi Ito. But as the film plunges deeper into the dark and gruesome, Jyaku discovers that the Legend of the Overfiend is not what it seems and that the future of the three realms may be strikingly different from what he is led to believe.