Earth braces for its final destruction in a collision with an onrushing planet, and only Dr. Zarkov can prevent doomsday. Taking Flash Gordon and Dale Arden captive, he takes off in a rocket to deflect the hurtling planet and save the world. The mad Zarkov, Flash and Dale survive a crash landing on Mongo, only to be captured by the diabolical Ming the Merciless. And the true adventure begins.