Sheriff Thomas of Fenton's Creek is puzzled when an elderly recluse is murdered. This first killing is followed swiftly by another, leaving the small town at the centre of an affair which has even the government in Washington alarmed. Oblivious to the maelstrom of violence, young Harriet Thorndike arrives from Boston to attend her uncle's funeral. In no time at all, her own life is in jeopardy as she is caught in a desperate search for the treasure which is said to lie up in the Superstition Mountains of Arizona.