Astronauts blast off to explore the moon on Rocketship X-M or "Rocketship eXploration Moon". A spacecraft malfunction and some fuel miscalculations cause them to end up landing on Mars. On Mars, evidence of a once powerful civilization is found. The scientists determined that an atomic war destroyed most of the Martians. Those that survived reverted to a caveman like existence.

Don Gallico is an inventor of stage magic effects who aspires to become a star in his own right. Just before his first performance his act is shut down by capricious manager Ross Ormond who wants Gallico's brilliant buzz saw effect for the act of The Great Rinaldi, an established star. With this defeat, and the humiliation of having already lost his wife Claire to Ormond, Gallico decides it is time to take matters into his own hands.

A down-and-out gangster hires a down-on-his-luck agent to make his girlfriend a recording star within six weeks.

When Dr. Anthony Edwardes arrives at a Vermont mental hospital to replace the outgoing hospital director, Dr. Constance Peterson, a psychoanalyst, discovers Edwardes is actually an impostor. The man confesses that the real Dr. Edwardes is dead and fears he may have killed him, but cannot recall anything. Dr. Peterson, however is convinced his impostor is innocent of the man's murder, and joins him on a quest to unravel his amnesia through psychoanalysis.