The C-class idol group, Ongaku Shoujo, under Pine Records is comprised of eleven girls. Despite lackluster sales and minimal fame, Producer Ikebashi and the members are determined to improve. In an effort to boost success, Ikebashi proposes adding a new member as a catalyst. An audition is held and it leads to the fateful encounter of Ongaku Shoujo with a girl named Hanako, who would soon become a legendary member of the group.