Pascal, le héros, est un homme sympathique, bourru et quelque peu candide. Il est crieur de journaux et vend France-Soir dans les rues. Un jour, après qu'il a vendu son paquet de journaux, Pascal est assis au bord de la Seine, lorsqu'un homme se jette à l'eau à quelques pas de lui ; Pascal se précipite et le sauve.
Knowing how much telephone repairman Mal Granger (Edmond O'Brien) likes to bet on the horses, small-time bookmaker Chippie Evans (Sammy White) proposes a scheme in which Granger's technical expertise would provide gangster Vince Walters (Barry Kelley) with race results in advance.
The film is a satire on the modern advertisement business. The plot mainly concerns the story of a commercial advertisement designer, Octave Parango (Jean Dujardin), who has an easy-going, highly paid job, and an active free life mainly consisting of drugs and random one-time sexual relationships. However, he starts growing weary of his job, and after having his first ever long-time relationship with fellow worker Sophie (Vahina Giocante) fail miserably, he organises a revolt against the advertisement business and his own life.
Eighteen-year-old Liz Taggart has gone to a lovers' lane with her boyfriend, Owen Clark, who has not yet been introduced to her parents. Unbeknownst to them, a psychopath named Harold Loftus has been watching them. Loftus knocks Owen unconscious and overpowers Liz, taking her to a shack.
During the closing days of the Second World War, six members of his Royal Canadian Air Force fighter squadron are killed due to a command decision made by pilot Ted Stryker (Dana Andrews). Years later, in civilian life in Ottawa, Ontario, Canada, a guilt-stricken Stryker goes through many jobs, and his marriage is in trouble.
Down-on-his-luck Los Angeles architect and builder Edward Shaw (Keith Andes) is approached by Doris Hillman (Angela Lansbury) with a business proposal: buying land together, on which he would build houses that she would then sell, using her experience as a former real estate broker. Her husband, Gus Hillman, a wealthy businessman, would be willing to contribute half a million dollars as capital for the venture.
Artist Trevor Stevenson (Meeker), an emotionally scarred World War II veteran, is on honeymoon in Acapulco with his bride Stella (Rule). Shortly after their arrival, two women are murdered. The audience is presented with clues pointing to Trevor's guilt or innocence depending upon one's point of view.
The blonde bombshell Joyce Bonniwell is in need of a private investigator. She hires Simon Lash, a Los Angeles lawyer with a great interest for books, who has become a private investigator by interest. He was also left by the altar by Joyce some years ago. Joyce needs to find her husband, Sam Bonniwell, who has gone missing. Sam has a history of amnesia attacks, and sometimes has a hard time taking care of himself. He is a very wealthy man, which is one of the reason why Joyce married him. Sam is the vice president of the Sheridan National Bank in Los Angeles.
Frank Enley (Van Heflin), returns home from World War II after surviving a German POW camp where the rest of his comrades had been murdered by guards during an escape attempt. The "war hero" is respected and praised for his fine character and good works in the California town of Santa Lisa, where he, his young wife and baby had settled after moving from the East. What his wife doesn't know is that Frank relocated them to get away from Joe Parkson (Robert Ryan), once his best friend, who also lived through the ordeal, though he was left with a crippled leg. In exchange for food, Frank had alerted the Nazi camp commander to their escape plans, thinking wrongly that the men would not be punished, and Joe is now determined finally to exact justice on Frank, whose location he has learned from a newspaper story commending him for his civic endeavors.
Temporarily blinded with his eyes bandaged, private detective Philip Marlowe (Dick Powell) is being interrogated by police lieutenant Randall (Don Douglas) about two murders.
Mike Callahan (Duryea) is an Irish émigré and war veteran working in Singapore as a private detective. He takes on a case from a former flame, now a nightclub singer. She thinks her husband Julian March (Knowles) is involved in criminal activities and asks him to help out.
Police chief Joe Conroy (Hayden) is relieved of his police duties after he accuses a "respected community man" Al Willis (Barry) of murdering a group of police officers. Despite his lack of authority, Conroy puts so much heat on Willis that the latter, making the excuse to his wife Helen (Marcia Henderson) that he needs time to clear his head, skips town for Border City, where he's living a double life as a hoodlum with bar-singer mistress Marianna (Grahame), whom he treats abusively.
A psychotic killer, Garland "Red" Lynch, uses a campaign of terror to force San Francisco bank teller Kelly Sherwood to steal $100,000 from the bank for him. Despite his threat to kill her or her teenaged sister Toby if she goes to the police, Sherwood contacts the San Francisco office of the FBI, where agent John Ripley takes charge of the case.