Planet Mongo breaks out of its orbit and is sent hurtling on a collision course with Earth. Renowned scientist Dr. Zarkov builds a rocket in order to investigate the impending disaster at close quarters. He is joined on his mission by Flash Gordon and Dale Arden, who have recently survived a plane crash, and the three soon find there is more to Planet Mongo than originally thought, not least the evil ruler Emperor Ming. Based on the original Flash Gordon comic strip series. Space Soldiers was the first of the Flash Gordon series to be made and given a budget of $350,000, a then unheard-of sum. The series, however surpassed all expectations and became an unqualified success.