The still very undead mummy experiences insane jealousy in this the third of Universal's Kharis thrillers. Although he was thought to have perished in a fire in The Mummy's Tomb (1942), Kharis (Lon Chaney Jr.) is once again wreaking havoc in the town of Mapleton, MA. Sent by the High Priest (George Zucco) to retrieve both Kharis and his ancient love interest, the Princess Ananka, from their resting places at New York's Scripps Museum, Yousef Bey (John Carradine) learns that the princess has turned to dust. Her soul, however, seems to have been reincarnated as Amina Mansouri (Ramsay Ames), an Egyptian exchange student studying with Mapleton Egyptologist professor Norman (Frank Reicher). The latter's experiments with brewing tanna leaves turn ugly when Kharis appears. Soon after, Amina's hair develops grey streaks and she experiences strange and unsettling trances, unsettling especially for boyfriend Tom Hervey (Robert Lowery). Investigating Professor Norman's strange death, Inspector Walgreen (Barton MacLane) sets a trap for Kharis, but the crafty mummy escapes with a prostrate Amina. Hiding in an abandoned mineshaft, Kharis, to his distress, learns that Yousef harbors more than a religious interest in the beautiful Amina and promptly kills him. With the reincarnated but rapidly decaying princess in his arms, the mummy, to the horrors of the townspeople in general and Tom in particular, blithely walks into a nearby swamp and slowly sinks into the quagmire.