Yukiguni no Oujisama
English title: The Snow Country Prince
Japanese title: 雪国の王子さま
Type: Movie
Episodes: 1
Source: Book
Genres: Slice of Life
Studios: Toei Animation
Producers: Shinano Kikaku
Duration: 1 hr 30 min
Rating: G - All Ages

Koichi and his sister Yuki befriend Hanaguro, a swan who has flown to Japan from Siberia. Hanaguro is attacked by a dog, and the cowardly Koichi flees, but that night he has a dream in which he is whisked away to the Kingdom of Snow Prince, where he finds the bravery to help the other swans.

(Source: The Anime Encyclopedia)