Otonokizaka High School is in trouble! With the number of students enrolling decreasing year after year, the school is slated to close when the current first-year class graduates. Honoka Kousaka, a second-year student, isn't going down without a fight. In her search for a solution, she discovers popular school idol group A-RISE and decides to form her own school idol group. Honoka forms's (pronounced "muse") with the support of her childhood friends Umi Sonoda and Kotori Minami in order to raise awareness and popularity of her school. Unfortunately, all of this is easier said than done. Eri Ayase, president of the student council, is passionately opposed to the formation of a school idol group and will do all in her power to prevent it.