S1.E5 ∙ Episode #1.5

Dr. Thomas Warren reviews the previously classified footage caught by serial killers Leonard Lake and Charles Ng as they worked to kidnap women and torture them into sexual submission. This film seeks to analyze the criminal mind and pinpoint the precise motives, profiles and personalities of the murderers from the case who were not only caught, but are still at large today.

Mathilde Stangerson just married her fiance, when she heard that Larsan, her cruel former husband, whom she believed to be dead, is actually very much alive. Taking refuge to her castle, she appealed to the journalist Rouletabille to protect her.

Criminal Frans Weeling realizes, after he has a revelation on the island Texel, he is only another link in the chain of the whole universe. This idea enlightens him, but also conflicts with his position and perspectives in the underworld.

Dave Britten, a bright young detective in the police force, captures one of J. C. Owen's henchmen and charges him with robbery. Owen then hires Raymond Cortell, a crooked lawyer, to act as the criminal's defense. Cortell not only keeps crooks and gunmen out of jail by manipulating legal technicalities, but spurs them to more crime by demanding large fees for his legal services. Cortell assigns the case to one of his unwary younger partners, Mary Kennedy, who is the daughter of police captain Jim Kennedy. Mary wins an acquittal by utilizing the tricks Cortell suggests, becoming adept at serving as a criminal "mouthpiece." Dave, Mary's fiancé, is dismayed by her action, and the two quarrel, but they make up, and she agrees to quit her job and marry Dave when he is promoted to lieutenant. Dave soon investigates a jewel robbery at Owen's office, and aided by the eye-witness account of a janitor and his own deductions, he charges Owen with murdering a diamond salesman and accuses him of carrying out the crime in a way in which no suspicion would fall on him. Mary is again the defense attorney for Owen, and by confusing the janitor on the witness stand with questions pertaining to the moonlight on the night of the murder and comparing his answer to an almanac, she obtains an acquittal. Mary becomes famous, but Dave and her father are angry at the tactics she has used. In order to pay Cortell, Owen robs a jewelry store and shoots Jim in the process. Mary at last realizes the error of her ways. The wounded Jim identifies Owen, and with Mary's help, Dave is able to capture him and to arrest Cortell for receiving stolen property. Jim is on his way to recovery, and Mary and Dave are reunited.

In 1929, middle-class bank clerk Eddie Clark, unhappy with his lot in life and jealous of prosperous George Bates, an ex-suitor of his loyal wife Agnes, steals $200,000 from his bank, with intentions of he and Agnes being in Mexico before the theft is discovered. Agnes tries to persuade him to return the money to no avail. He is caught and sent to prison without revealing the hidden location of the loot, figuring to get it and live in luxury when his ten-year term is over. His case has received much publicity and nearly every inmate in the prison attempts to wrest the information from him. Gangsters on the outside arrange with convicts Clyde Sutter and Butch McQuinn to get the secret from him. Agnes, who has taken a waitress job in a nearby city, is also trying to find the money with the intention of returning it and getting Eddie a reduced sentence. Sutter's plan is to involve Eddie in a prison break and turn him over to the gangsters on the outside. Butch is shot during the break, and Eddie is the only one to escape. He meets Agnes in an old warehouse but she has been trailed by gangsters Kelvin and Benson. They beat him up but his life is saved by the arrival of the state police. He is returned to prison with an additional five years added to his sentence. He is released in 1947 and makes his way to the money's hiding place - a cemetery plot he had bought in 1929.

An army sergeant recognises a young recruit as the man responsible for his brother's death, while attempting a robbery.