In the upper reaches of the Amazon River, a scientific team discovers an amphibious creature, a living missing link. The creature is captured and falls in love with the female assistant of the leader of the research team. The lonely creature kidnaps her, and the scientist mounts an effort to reclaim his sweetheart and return the creature to his watery home.

The mummy, is accidentally revived after 3,700 years by a team of British archaeologists. It is revealed in a flashback that he was a high priest, embalmed alive for trying to revive the vestal virgin whom he loved, after she had been sacrificed. Alive again, he sets out to find his lost love.