Mysterious Doctor Satan is a 1940 film serial named after its chief villain. Doctor Satan's main opponent is 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.It was directed by the directorial team of William Witney and John English.