While Kinnikuman is away on holiday with Mari-sans kindergarten class at Easter Island, a young wheelchair-bound boy named Kouichi-kun expresses his disappointment in being accompanied by an idiot like Kinnikuman. He would much rather be spending time with his favorite Seigi Choujin Buffaloman. Meanwhile, other Seigi Choujins are also enjoying their holidays at various ancient landmarks around the world.
Seigi Choujin vs. Ancient Choujin is the third theatrical film based on the anime series Kinnikuman. It was released in Japan on March 16, 1985 alongside Gu-Gu Ganmo, Dengeki Sentai Changeman, and Tongari Boushi no Memoru. It is set after the Golden Mask Arc.This film is the first to feature anime original character Kinkotsu-Obaba. Although this film is set after the Golden Mask Arc, the character Geronimo does not appear as an active fighter until the next film. He does, however, appear in flashbacks to the Golden Mask conclusion. This is also the second time voice actor Ichirou Nagai appears in a Kinnikuman work playing the main villain. He had previously appeared in the TV Special. It also features the return of voice actors Kouzou Shioya and Yasuo Tanaka, who had previously appeared in the first film Stolen Championship Belt.(Source: Wikipedia)