On the way to her first day of high school, Eri Kumagai is entranced by a girl's melodious singing. However, the moment shatters when the girl accidentally steps on a cat's tail. Eri tries to forget the incident until the same girl, now claiming to be Haru Chitose instead of Chiharu Yuzuka, barges into their class late with the cat in tow. To Eri's dismay, they end up being roommates in the dorm. Despite Eri's frustrations with Haru's eccentricities, things escalate when Haru delves into Eri's secret life as an online composer. Eri is outraged when Haru expresses a desire to collaborate, leading to a clash of wills. Can these two opposites bridge their differences and find harmony?