A rogue planet is 'rushing madly toward the earth.' Impending doom creates worldwide pandemonium. But maverick scientist Dr. Zarkov hopes to stay disaster by travelling to the new planet in his experimental rocket. Two chance-met strangers, athletic Flash Gordon and damsel in distress Dale Arden, go with him. Arrived, the trio find Mongo to be a planet of wonders, warring factions, and deadly perils, its orbit controlled by Emperor Ming who has his own sinister plans for earth. Can our heroes, armed only with science and sex appeal, stop him?