Feature version of the 1938 film serial FLASH GORDON'S TRIP TO MARS. Flash Gordon fights Ming the Merciless once again to ensure the survival of the Earth.

A rich but naive young woman is in possession of some priceless jewels. She herself doesn't know it, but a gang of jewel thieves does.

Kurt Ingston, a rich recluse, invites the doctors who left him a hopeless cripple to his desolate mansion in the swamps as one by one they meet horrible deaths.