The island kidnapping plot doesn't hold up, and it knows it, the movie banks entirely on you already loving these characters enough to watch them riff for ninety minutes. Mousse finally gets a story that isn't just "pathetic comic relief," which means fans invested in him actually get something. The animation during the action sequences is genuinely sharp for 1992, even when the premise underneath is running on fumes.

A storm wrecks Kuno's luxury yacht, leaving Ranma, Akane, and the rest of the group stranded on a deserted island. What begins as a simple survival situation turns stranger when the girls vanish one by one, taken by Prince Toma, the young ruler of the floating island of Togenkyo. A magical spring there turns anything it touches male, so would-be grooms resort to kidnapping brides, and Akane is among the captives. Ranma sees opportunity in catastrophe: that same water could cure his own shape-changing problem. To rescue Akane and the others, he disguises himself as a girl and enters an anything-goes martial arts bride contest, facing events like survival flower arranging and obstacle-course cooking against a crowd of other kidnapped concubines. The film mixes slapstick comedy with action, ecchi gags and an island adventure that never takes itself seriously.