Kōsei is a former child prodigy in playing piano, dubbed the "Human Metronome" for his mechanical accuracy, a product of his mother Saki's strict method of teaching. When Saki dies, Kōsei becomes unable to hear the sound of his piano playing and he gives up on it. Two years later, he takes up the piano again after Kaori Miyazono persuades him to become her accompanist. Influenced by her emotional and unrestrained playing style, Kōsei falls in love with her.