The manga tells a romance story with the themes of "music x one-sided love." Nino, a girl who loves singing, made a childhood promise with her first crush Momo and song-composing Yuzu to someday find her voice. The three went their separate ways, but Nino kept her promise and continued to sing. Years later, the three are now high school students, and Nino is drawn into the world of band clubs.
Summary taken from: MyAnimeList