High school student Totsuko has the ability to see people as colours, and is particularly fascinated with the colour she sees in her classmate, Kimi. After following Kimi to a used bookstore, Totsuko accidentally implies she can play piano, leading to her joining a band with Kimi, who can play guitar, and Rui, a boy who collects musical equipment and plays the theremin. The trio`s friendships develop as they write music and confront issues in their home lives.