Hoshi o ou kodomo (2011) aka Children Who Chase Lost Voices from Deep Below

A coming of age story involving young love and a mysterious music, coming from a crystal radio left as a memento by an absent father, that leads a young heroine deep into a hidden world.

Director: Makoto Shinkai
Writer: Makoto Shinkai (story)
Stars: Hisako Kanemoto, Kazuhiko Inoue and Miyu Irino