Judoka Marc Saint-Clair tries to save the world from nuclear disaster fighting Chinese and Russians.

Marc Saint-Clair wins a medal at a Kendo tournament in Tokyo, Japan. He offers his medal to his American friend Clyde as a good luck charm. As an airline pilot, Clyde accompanies a C.IA. agent, Finn, in a secret mission to investigate over China regarding a supersonic bomber. While Clyde is absent, Marc has an affair with Clyde's girlfriend Jennifer, before he learns of the pilot's disappearance. In grief, Marc goes by boat to Hong Kong, trying to know what happened to Clyde. One month later, a young Chinese woman who escaped from an organization, the Black Dragons, reaches Marc and informs him that Clyde is alive and detained in a secret island. Starting from there, Marc (a.k.a. Judoka) must face the henchmen of this organization with his judo skills and try to save the world, along with the C.I.A. and the bumbling Jennifer..—Campy60sFan