Mysterious Doctor Satan

A mad scientist named Dr. Satan plots to steal key pieces of technology to enable him to build an army of robots based on his prototype to conquer America. The only one standing in his way is Bob Wayne, who fights Satan as the enigmatic Copperhead. Mysterious Doctor Satan is a 1940 film serial named after its chief villain. Doctor Satan's main opponent is the masked mystery man, "The Copperhead", whose secret identity is Bob Wayne, a man searching for justice and revenge on Satan for the death of his step-father. The serial charts the conflict between the two as Bob Wayne pursues Doctor Satan, while the latter completes his plans for world domination.

Directed by John English, William Witney, Mysterious Doctor Satan leans on a strong ensemble — Eduardo Ciannelli, Robert Wilcox, William Newell — to carry a story that balances spectacle with character.

The film landed with audiences for its craft and performances, and remains one of the most talked-about action titles of 1940.