Piano is about a secondary two schoolgirl by the name of Miu who has been playing the piano from a very young age. She is a very quiet girl. There's a senior in her school who she admires and likes but just looking at him alone already requires a lot of effort on her part, let alone...

Her life experiences are being depicted by the rhythm of the tunes she plays with her piano, such as happy times being with friends and family, not to mention love of course.