Misaki, a pianist who runs a piano studio from her home with her husband's understanding and support, noticed an issue with her piano while preparing for a recital and contacted a tuner. However, the tuner was too busy to assist that day. Though referred to another technician, she found his attitude unpleasant and ultimately decided to hire Kagiya, a tuner she had never worked with before. Yet when Kagiya arrived with his rude and disrespectful behavior, Misaki grew increasingly annoyed and tried to send him away—but things took a dark turn.