When a cold medicine causes Sach to be able to smell diamonds, he and the rest of the Bowery Boys are induced by a diamond dealer to accompany him to Darkest Africa in search of a legendary cache of them.

Hard-boiled archeologist Mark Brandon is searching for ancient tombs in Egypt when he is approached by beautiful Ann Mercedes, who convinces him to help her fulfill her deceased father's life's ambition - to provide solid proof of the biblical Joseph's travels in ancient Egypt. As an ex-pupil of Ann's father, Mark accepts and the two embark on a search for the tomb of the Pharoah Ra Hotep, said to have had some connection with Joseph. The trail to the tomb is fraught with intrigue, betrayal, murder, and the possibility that the tomb itself has been emptied of all its artifacts by ancient looters.

A civilization of gorgeous cavewomen abduct men for mating purposes. One of their victims is Engor, who seems to be smarter than the rest of the men. He discovers fire, battles a monstrous giant and attempts to win the hand of the prehistoric queen.