Sandra Carpenter is a London-based dancer who is distraught to learn that her friend has disappeared. Soon after the disappearance, she's approached by Harley Temple, a police investigator who believes her friend has been murdered by a serial killer who uses personal ads to find his victims. Temple hatches a plan to catch the killer using Sandra as bait, and Sandra agrees to help.

Two con artists join forces and pose as brother and sister. He then meets rich widows through the "personals" sections of newspapers, marries them, and both kill the widows for their money.