When the Rinkai League launches, it brings back women's competitive cycling in Japan, a sport that began soon after World War II but stopped holding organized races after only fifteen years. The league's early races draw attention, and women from across the country join in pursuit of professional careers. Izumi Itou loves cycling but hesitates to bet her future on racing, even with her friends urging her on. Her outlook shifts when she learns her grandmother was once a champion rider, and the older woman offers to coach her. At a training school, Izumi meets Hiratsuka, who becomes her rival and close friend, and a formidable Swiss competitor intent on ruling the field pushes Izumi to give everything on the track.