Kinnikuman II Sei: Muscle Ninjin Soudatsu sen! Choujin Daisensou
Japanese title: キン肉マンII世 マッスル人参争奪！ 超人大戦争
Alternative titles: Kinnikuman II: Muscle-Man Competition! Great War, Kinnikuman Second Generations: Muscle-Man Competition! Great War, Massuru Ninjin Soudatsu! Choujin Dai Sensou, Muscle Ginseng Competition! The Great Choujin War, Ultimate Muscle, Kinnikuman Nisei
Type: Movie
Source: Manga
Episodes: 1
Status: Finished Airing
Aired: Jul 20, 2002
Duration: 40 min
Rating: PG-13 - Teens 13 or older
Studios: Toei Animation
Genres: Action, Comedy, Drama, Romance
Themes: Martial Arts, Samurai

In order to save a princess, Mantarou (Kid Muscle) and the gang must find a special ginseng. They are later joined by Kevin Mask. 

(Source: Wikipedia)