isumi Natsuki is a member of the karate club at Goujyu High School. Strong and very skilled, only the captain of the group, Masaoki Yanagisawa, is a match for her. Her life starts to get really complicated when a student named Rina Takaoka is transferred to her school and becomes her classmate. Takaoka's former colleagues are set to punish her for having left Jotoh Academy, a school famous for it's martial arts.