Kucabara was recently banished and stripped of his powers. In order to regain his powers, he needs Dark Matter which is found from human sinners. He decides to become a Defense Devil in order to get dark matter. A Defense Devil's duty is to prove the innocence of human sinner of his or her crime; once that is done, a Defense Devil shall be allowed to take the sinner's dark matter. Kucabara then must prove the sinner's innocence before a Shinigami takes the sinner to hell. One day, Kucabara's friend Funi arrives and tells him the demon world is in dishevel and Kucabara must return to save it. With the aid of his friends, Kucabara infiltrates the demon world with Bichura the dragon demon and the female exorcist named Idamaria, and discover the source of the chaos to be Kucabara's younger brother, Legato, and set out to confront him. Eventually, they realize Legato was gathering energy to destroy the angels who reign control over Hell. After confronting Elimona and the angels, Kucabara is called by God and is taken to heaven. Kucabara returns to his friends and the series ends with him recruiting his friends to defend God who has been betrayed by his angels.