Ranma ½: Kessen Tougenkyou! Hanayome wo Torimodose!
English name: Ranma ½: Nihao My Concubine
Genres: Adventure, Comedy
Type: Movie, Episodes: 1
Aired: Aug 1, 1992
Studio: Studio Deen
Source: Manga
Rating: PG-13 - Teens 13 or older
Synopsis:
Ranma and the gang are invited to a boating trip with Kuno. Unfortunately, a storm destroys the yacht and everyone is stranded on a remote island. The whole situation goes even more awry when one by one, the girls disappear without a trace. Ranma then finds out that the girls are abducted by Toma, ruler of the island, as part of his personal harem.

(Source: ANN)