Lost Serenade.

Kaori (Nori Sato) runs a small piano studio. One of her students is Yuu (Uwa Ishibashi). On the way from a recital, Kaori is sexually assaulted by Yuu's father (Kentaro Furuyama). Kaori later learns Yuu has also been sexually abused by her father. Kaori and Yuu share each other's pain and eventually Kaori decides to fulfill Yuu's wish.