The bullet car used by the clay people is the same one used in the scenes on Saturn in Buck Rogers (1939). Much of the background music was originally used in Bride of Frankenstein (1935). Also, the song that played in the background during the sequence recapping the previous chapter's events was the theme for The Invisible Man (1933). This was the final appearance of Jean Rogers as Dale Arden. The serial is based on the comic strip storyline "Flash Gordon and the Witch Queen of M ...[Read Story ]