Tony Wendice (Ray Milland), an ex-professional tennis player, lives in a ground floor flat with his socialite wife, Margot (Grace Kelly). Tony retired after Margot complained about his busy schedule and she began an affair with American crime-fiction writer Mark Halliday (Robert Cummings), which Tony secretly discovered. Tony devises a plan to have Margot murdered.
Irene Wagner (Bergman), the wife of prominent German scientist Professor Albert Wagner (Wieman), had been having an affair with Erich Baumann (Kreuger). She does not disclose this to her husband, hoping to preserve his innocence and their "perfect marriage". This fills her with anxiety and guilt. However, Johann Schultze (Mannhardt), Erich's jealous ex-girlfriend, learns about the affair and begins to blackmail Irene, turning Irene's psychological torture into a harsh reality. When Irene finds out that the extortion plot is truly an experiment in fear, she is driven into a homicidal/suicidal rage. But she is saved from suicide by her husband at the last minute, both sorry for what they did.
Railroad supervisor Carl Buckley (Broderick Crawford) gets fired from his job. He persuades his seductive wife to pay a visit to an important railroad customer in order to try to get his job back. When Buckley suspects that his sexy, younger wife Vicki (Gloria Grahame) has done more than just talk with the rich old magnate John Owens (Grandon Rhodes), he smacks her around. He then jealously stalks his rival, finally stabbing him to death in a train compartment. Locomotive engineer and Korean War vet, Jeff Warren (Glenn Ford) observed Vicki in the vicinity of the murder, but shields her at the inquest, as she sets his pulse racing. The two begin an affair which is hard to keep quiet in such a small town. Vicki then starts scheming for Warren to kill her increasingly drunk and violent husband.
In Honolulu, a DC-4 airliner prepares to take off for San Francisco with 17 passengers and a crew of 5. Former captain Dan Roman (John Wayne), the flight's veteran first officer known for his habit of whistling, is haunted by a crash that killed his wife and son and left him with a permanent limp. The captain, Sullivan (Robert Stack), suffers from a secret fear of responsibility after logging thousands of hours looking after the lives of passengers and crew. Young second officer Hobie Wheeler (William Campbell) and veteran navigator Lenny Wilby (Wally Brown) are contrasts in age and experience. Stewardess Spalding (Doe Avedon) attends her passengers, each with varying personal problems, including jaded former actress May Holst (Claire Trevor), unhappily married heiress Lydia Rice (Laraine Day), aging beauty queen Sally McKee (Jan Sterling) and cheerful vacationer Ed Joseph (Phil Harris). Spalding befriends the terminally ill Frank Briscoe (Paul Fix) after being charmed by his pocket watch. A last-minute arrival, Humphrey Agnew (Sidney Blackmer), causes the crew concern with his strange behavior.
After breaking his leg photographing a racetrack accident, professional photographer L. B. "Jeff" Jefferies (James Stewart) is confined to his Greenwich Village apartment, using a wheelchair while he recuperates. His rear window looks out onto a small courtyard and several other apartments. During a summer heat wave, he passes the time by watching his neighbors, who keep their windows open to stay cool. The tenants he can see include a dancer he nicknames "Miss Torso", a lonely woman he nicknames "Miss Lonelyhearts", a composer-pianist, several married couples, a middle-aged sculptor, and Lars Thorwald (Raymond Burr), a traveling jewelry salesman with a bedridden wife.
When the Japanese freighter Eiko-maru is destroyed near Odo Island, the Bingo-maru is sent to investigate, only to meet the same fate with few survivors. A fishing boat from Odo is also destroyed, with one survivor. Fishing catches mysteriously drop to zero, blamed by an elder on the ancient sea creature known as "Godzilla". Reporters arrive on Odo Island to further investigate. A villager tells one of the reporters that "something large is going crazy down there" ruining the fishing. That evening, a ritual dance to appease Godzilla is held during which the reporter learns that the locals used to sacrifice young girls. That night, a large storm strikes the island, destroying the reporters' helicopter, and an unseen force destroys 17 homes, kills nine persons and 20 of the villagers' livestock.
The film credits open to the scene of a moving police car in the streets of Alhambra, California. The car stops at a police station, and the officers inside it transport their drunk prisoner to the station. Inside the station, Marilyn Gregor (Dolores Fuller) meets Inspector Johns (Lyle Talbot) and Bob Lawrence (Steve Reeves). Through their discussion, the viewers learn that her brother Don Gregor (Clancy Malone) had been arrested for carrying an unlicensed handgun. She has just posted bail for him, and the two officers warn her that she would forfeit if her brother fails to show up for his trial. They release her brother, but they refuse Don's request to return his handgun. As the Gregor siblings leave, John Muses about the son of a great doctor being a jerk. Lawrence suggests it could be a result of the "sins of the father". Johns suspects the young man was an associate of gangster Vic Brady (Timothy Farrell).
In post-war America, the President of the United States is scheduled to journey through the small town of Suddenly, California. Claiming to be checking up on security prior to his arrival, a group of FBI agents arrive at the home of the Bensons, on top of a hill that looks down upon the station where the Presidential train is scheduled to stop. However, they soon turn out to be assassins led by the ruthless John Baron (Frank Sinatra), who take over the house and hold the family hostage.
The entire film takes place over the course of three days.
Max, a decent and principled gangster, has dinner at Madame Bouche's restaurant, a hangout for criminals, with his longtime associate Riton, their burlesque-dancer girlfriends, and his protege Marco. A newspaper is seen to mention eight bars of stolen gold. The group goes to Pierrot's nightclub, where the girls perform. Max gets Marco a job as a drug dealer working for Pierrot. After the show, Max finds Riton's girlfriend Josy making out with Angelo, another gangster.
Peter Denver (Van Heflin) is a renowned Broadway producer attending a party—hosted by the viciously haughty and celebrated actress Carlotta "Lottie" Marin (Ginger Rogers) and her quiet husband Brian Mullen (Reginald Gardiner)—when he meets Nancy "Nanny" Ordway (Peggy Ann Garner). Ordway is a seemingly naïve, 20-year-old, aspiring writer, who hopes to make it big in New York. She convinces a reluctant Denver to let her use his apartment to work during the day, while his wife, Iris (Gene Tierney), also a famous actress, is away, but with her permission. After the Denvers return from the airport and find Nancy hanging dead in their bathroom, a variety of people Ordway has recently met in New York begin to reveal deeper and darker connections with her. Lt. Bruce (George Raft), the detective assigned to the case, soon discovers that this apparent suicide was in fact a homicide and believes that Denver, quickly suspected of having an affair with Ordway, is the murderer. Denver evades arrest and seeks clues to discover the real murderer; the case becomes cluttered when he and Lt. Bruce independently realize that Ordway's dealings in New York have not been as innocent as her superficial personality.
Crystal Benson is a single mother living in a small town in New Mexico. One night she feels a man is stalking her. She grabs a gun and makes a series of arrangements anticipating his own death. She prepares a tape with a message for her teenage daughter, who (in flashback) speaks about her relationship with Steve Blackford, who, has good reason to hate her.
Kalu is a migrant taxi-driver in Mumbai, He has two women who love him and would like to marry him. Kalu first wants to establish himself and become rich, before he can even think of marriage.
Matt Kelly (Robert Ryan) is released from jail and skips town in his boat without paying outstanding storage fees. Back in his home town he is hired by his old friend Jim Kimmerly (Brian Keith), the head of the local salmon fishermen who have formed a canning co-operative. The fishermen are battling against an organised gang who are robbing the fishing traps. Matt however, short on cash, joins the raiders, whilst Jim, unaware of his duplicity, keeps covering for him amongst the other fishermen. Furthermore Kelly has his eyes upon Jim’s fiancée, Nicki (Jan Sterling). Kelly's recklessness eventually causes the loss of Kimmerly's fishing boat in a glacier avalanche. He tries to make amends for his misdemeanours in an act of self-sacrifice.
'Doc' Penny (Ted de Corsia) and his gang rob a gasoline station and in the process a police officer is killed and one of the gang members is wounded. The wounded thug imposes himself on Steve Lacey (Gene Nelson), an ex-con trying to start a new life, and demands he call a disreputable doctor for help. The doctor arrives, but too late. The gang member is dead. After his death, Lacey calls his parole officer who involves a hard-nosed cop, Detective Lieutenant Sims (Sterling Hayden), who doesn't think he can reform.