On her way to her first day of high school, Eri Kumagai is captivated by a girl's singing. Her song is beautiful but ends abruptly when the girl steps on a cat's tail and disrupts the moment. Eri pushes this out of her mind until that same girl rushes into her class late, cat in hand, and claims that the name on the attendance list—Chiharu Yuzuka—is her "false name" and she is actually called Haru Chitose. Much to Eri's distaste, she cannot escape the eccentric Haru, as the two happen to share the same dormitory room. Haru causes one headache after another, but when she snoops around in Eri's laptop and discovers that she is an online composer, Eri is furious. Haru, enamored by Eri's music, desperately wants to sing with Eri, but Eri is dead set against it. Will the two be able to find common ground?