Hoshi, a shy high school senior, loses her father in a car accident. Suddenly, a delegation of local gangsters led by the dashing and handsome Sakuma, the underboss of the Medaka family, shows up at her doorstep. The senior boss has passed away, and Izumi’s father was his direct relative. Now, only this fragile young woman can save the small clan, which is being squeezed by brazen rivals who have forgotten the yakuza’s code of honor. Upon learning that her father’s death was no accident, Hoshi sets aside her textbooks and proclaims herself the eighth kumite of the Medaka family.