An American photographer in Rio de Janeiro becomes involved in the world of “knife culture” when he sets out to find the killer of one of his models.
Dr. Ernest Tindal kills his wife and plants clues pointing to her lover, Frank Marsh. Vera, Frank’s sister, enlists the aid or reporter Russell Kirk in proving the innocence of her brother. Detective McKinley thinks that gangster Jack Reed is involved and shoots Reed when he attempts to escape. Reed gets away but goes to Dr. Tindal for treatment of his wound and Tindal kills him on the operating table. Kirk has uncovered some new evidence and confronts Tindal with it.
Delia Peletier has been paid to have a child for a wealthy man who wants an heir. She has the baby and turns it over to her “employer,” but subsequently decides she wants the child back. She hires three men to kidnap the child. The quartet hides out in the house of Bernard Lapin, a nuclear scientist they believe to be away on business. Lapin returns, however, and becomes romantically involved with Delia.
A millionaire is found murdered in his apartment. Suspicion falls on a variety of suspects, including his fiancé and her parents, the butler, and a professional mentalist known as The Great Gambini.
During a police strike in Nova Scotia’s capital city, a gang of hoodlums end up unintentionally causing the owner of a gay bar to be killed. This escalates into a string of murders with a lone survivor trying to not be next.
Edmund Lowe plays Barrymoresque stage actor Cory Williams, who vaingloriously tries to solve a bizarre series of murders. Though the killings take place in the heart of New York, the victims are killed by the venom of a rattlesnake. It turns out that the killing has a vendetta against theater people, and Williams may be next on the list.
When 21-year-old Melissa Collins commits suicide, her guardian, the domineering American newspaper publisher William T. Marshall, searches (in flashback) for a reason. He finds it in a letter he receives from Melissa, after her death. In this, she asks Marshall to take revenge on her lover, who caused her such pain he made life not worth living. Marshall hires a professional criminal to plot the murder, with the proviso that the victim undergo the torments of the damned before he is finally killed. Trouble is, the wrong man is targeted for the publisher’s revenge.
Rookie policewoman Christine Miller volunteers to go undercover to avenge her father’s death. Posing as a drug dealer, Christine inveigles her way into a vicious narcotics ring. Inevitably, she is found out, and it’s up to police-lieutenant Mike Trent, who’s fallen in love with Christine, to come to her rescue.