在这部钢琴恋曲动画片中,美雨（川澄绫子 配音）要去上音乐课，却发现自己忘记带乐谱了，她闷闷不乐的躲在音乐教室里，因为害怕遭到白川老师（宫本充 配音）的责骂而不敢去上课。美雨的好友优希（川上伦子 配音）找到了美雨，说服她翘课，向来都循规蹈矩的美雨同意了。
美雨和优希来到了CD店内，店里优美的背景音乐让美雨开始后悔逃了课，看出了美雨的心思，优希鼓励美雨，让美雨鼓起勇气去上课。当美雨到达教室时，已经迟到很久了，让美雨没有想到的是，白川老师非但没有责骂他，反而宽容的让她进行即兴表演。在美雨的演奏中，流露出了丝丝的忧郁，这些都被敏锐的白川察觉了。
Miu used to love the piano. As a little girl, the music made her heart soar, and she eagerly shared her songs with everyone around her. Now an introverted teenager, she's become too shy to express her feelings - even through her music. Her piano teacher, the moody Mr. Shirakawa, has become impatient with her inability to reach the next level. When Miu develops a crush on Takahashi, her teacher notices a sudden and remarkable change in her playing. Can he help her find the courage to share both her heart and her music once more?
