A woman signs on as housekeeper in the home where her friend disappeared.

After learning that her late husband's estate consists of little more than a stamp album, Claire Marrable moves to a remote desert section of Arizona and begins hiring a series of housekeepers, all of whom have considerable savings and no immediate family. She then fleeces them of their money, murders them, and buries them in her garden. Her latest employee is Mrs. Alice Dimmock, who is posing as a housekeeper in an attempt to locate her friend Miss Tinsley, who disappeared after going to work for Mrs. Marrable. Aiding the investigation is Alice's nephew, racing car builder Mike Darrah. Mike is attracted to Mrs. Marrable's neighbor, widow Harriet Vaughn, who lives with her nephew Jim and a dog that often digs in the Marrable garden. When Mike learns that Miss Tinsley withdrew her savings before disappearing, he warns Alice of imminent danger, but it is too late; Mrs. Marrable beats the housekeeper into unconsciousness during a furious struggle and puts her in a car, which she sinks in a nearby lake. The body is found just as Mrs. Marrable begins to suspect that Harriet has some knowledge of the murder; to protect herself, she drugs both the young widow and her nephew, then sets fire to their home. The next morning, however, Mrs. Marrable awakens to find the Vaughns rescued and her garden of corpses unearthed. Unable to cope with the final blow--that her husband's stamp album was actually worth $100,000--she smiles insanely at Mike and asks him to drive her to Tucson so she can look for work as a housekeeper.