Raoul Leduc is a police inspector trailing a spy who plots to kidnap an important American atomic scientist. Joe Victor a gangster who is hired to carry out the abduction, balks when he learns what is at stake and helps Leduc out instead.

Agnes "Astra" Huston, a fortune teller at a run-down fair, is found strangled in her bedroom. As the police question five suspects, their interactions with her are shown in flashbacks from their point of view.

Eddie Darrow, seeking a mobster's widow in Macao, gets involved in a casino owner's affairs.

Steven Kenet, suffering from a recurring brain injury, appears to have strangled his wife. Having confessed, he's committed to an understaffed county asylum full of pathetic inmates. There, Dr. Ann Lorrison is initially skeptical about Kenet's story and reluctance to undergo treatment. But against her better judgement, she begins to doubt his guilt.

A newsman tracks down a phantom killer of murder-trial jurors.

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.

Unsuccessful writer Aylmer Franklyn takes the chance to change identities after he discovers a corpse. However, he soon finds himself accused of the murder of a maid at a near-by boarding house.

After committing a murder, a man locks himself in his apartment and recollects the events that led him to the killing.

A criminal known as Thunderbolt is imprisoned and facing execution. Into the next cell is placed Bob Moran, an innocent man who has been framed and who is in love with Thunderbolt's girl, without knowing of their relationship. Thunderbolt hopes to stave off the execution long enough to kill young Moran for romancing his girl.

A family man – desperate for a job – latches onto a friend who encourages him into being a criminal.

Gentleman gangster Max and his partner, Riton, pull off their last, most successful heist and find themselves comfortable enough to retire in the style they enjoy. However, Max confides the details of the theft to his younger mistress, Josey -- who has secretly taken up with ambitious young rival gangster Angelo. Angelo then has Riton kidnapped and demands the stash of gold as ransom, which threatens Max's dreams of the perfect retirement.

As a string of brutal murders plague the city, two undercover detectives race to solve the mystery and unmask the killer. Their only clues: each victim is a former cop and each has a blood-red letter painted on their body. How many will have to die before the killer spells out their message in blood?