A little in spite of him, Koichi has become the pupil of Knuckle Duster, a hero without alter who practises a rather expeditious justice... Since then, the student's little house has been regularly invaded by the old irascible fighter as well as by Pop Step, a local celebrity who decided to help them. But the trio still ignores the identity of his main opponent... Kuin Hachisuka may be only a high school student, it is she who manages the traffic of trigger in the neighborhood, and this super-villain half-time has not finished sowing chaos in the city!