The tranquility of a small town is marred only by sheriff Tod Shaw's unsuccessful courtship of widow Ellen Benson, a pacifist who can't abide guns and those who use them. But violence descends on Ellen's household willy-nilly when the U.S. President passes through town... and slightly psycho hired assassin John Baron finds the Benson home ideal for an ambush.
While in London trying to nab several fugitives who stole a million dollars from a U.S. Treasury vault, American federal agent Dennison (Dennis O'Keefe) assists Scotland Yard Insp. McClaren (Philip Friend) in his search for a missing atomic scientist (Paul Hardtmuth). The detective duo discovers that the key to solving both cases may rest with the scientist's daughter (Margaret Sheridan) and her fascinating diamond.
Bank teller Mike Donovan (Barry Sullivan) takes the first step on the road to Perdition when he fails to report a $49,000 shortage. Accused of theft, Donovan is fired from his job. He is then prevented from finding other employment by Javert-like insurance investigator Gus Slavin (Charles McGraw). Despite many setbacks, Donovan attempts to clear his muddied name.
When several women are found mutilated and murdered, the Paris police are baffled as to who the killer may be. All evidence points to Dupin, but soon it becomes apparent that it is someone (or something) stronger and deadlier than a human.
A man looking for his fortune in a mine decides to tempt his partner with his much younger wife. The goal? To catch them "in the act" and kill him without consequence.
Ambrose C. Park, left on a park bench as an infant with an impulsive need to find his parents, is an assistant to a diamond cutter. Shyster lawyer Remlick, in a strategy to get a fabulous uncut diamond through Ambrose, arranges for Emily Drummon, Duke Fargoh and Maggie Drummon to pose as Ambrose's long-lost parents and sister. The diamond, through many comic situations, is acquired and the gang is going to have Ambrose cut the diamond, and relieve him of the two stones and his parental illusions at the same time. But Maggie, who has no taste for the deception, tips Ambrose off and a wild chase ensues. At the end, Ambrose is very happy as he can now marry his "sister."
Reformed parolee Steve Lacey is caught in the middle when a wounded former cellmate seeks him out for shelter. The other two former cellmates then attempt to force him into doing a bank job.
After the suspicious suicide of a fellow cop, tough homicide detective Dave Bannion takes the law into his own hands when he sets out to smash a vicious crime syndicate.
Whitney Cameron is in a quandary: he's attracted to his beautiful sister-in-law, Lynn, but also harbors serious suspicions about her. Her husband, Cameron's brother, died under mysterious circumstances, and now that the death of her stepchild, Polly, has been attributed to poisoning, he suspects that Lynn is after his late brother's estate, and killing everyone in her way.
Chicago cop Johnny Kelly, dissatisfied with his job and marriage, would like to run away with his stripper girlfriend Angel Face, but keeps getting cold feet. During one crowded night, Angel Face decides she's had enough vacillation, and crooked lawyer Biddel has an illegal mission for Johnny that could put him in a financial position to act. But other, conflicting schemes are also in progress...