A Western agent is sent to Communist China in order to retrieve an important agricultural enzyme. What he does not know is that there is a bomb implanted in his head; the forces behind his mission will detonate it if he fails to carry out the assignment.
The film is set in Moscow in 1958 and 1979. The plot centers on three young women who come to Moscow from smaller towns: Katerina, Lyudmila, and Antonina. They are placed together in a workers' dormitory apartment and eventually become friends. Antonina is seeing Nikolai, a reserved but kind young man whose parents have a dacha in the country. Katerina (Vera Alentova) is a serious, upstanding woman who strives to earn her chemistry degree while working at a factory. She is asked to house-sit an apartment for her well-to-do Moscow relatives (a famous professor's family) while they are away on a trip. Lyudmila (Irina Muravyova), a flirty go-getter looking for a well-to-do husband while working at a bakery, convinces her to throw a dinner party at the apartment, and pretend that they are the daughters of Katerina's professor uncle, as a ploy to meet successful Muscovite men. At the party, Lyudmila meets Sergei, a famous hockey player, who falls in love with her and marries her even after discovering the truth about her origin. Katerina meets Rudolf (Yuri Vasilyev), a smooth talker who works as a cameraman for a television channel. He charms Katerina and then forces himself onto her. During Antonina and Nikolai's wedding, Lyudmila and Antonina find out that Katerina is pregnant. Upon discovering that Katerina is not the daughter of a professor, Rudolf refuses to marry her and believes that she is going to abort the fetus. Rudolf's mother stops by Katerina and Lyudmila's room in workers' dormitory to tell Katerina to stop bothering her son and offers her money, which Katerina refuses. Katerina finds out that it was actually Lyudmila who was calling Rudolf's mother pretending she was Katerina to demand child support. This leaves Katerina alone with the baby.
Cheng Huan (Richard Barthelmess) leaves his native China because he "dreams to spread the gentle message of Buddha to the Anglo-Saxon lands." His idealism fades as he is faced with the brutal reality of London's gritty inner-city. However, his mission is finally realized in his devotion to the "broken blossom" Lucy Burrows (Lillian Gish), the beautiful but unwanted and abused daughter of boxer Battling Burrows (Donald Crisp).
Catherine Sloper (Olivia de Havilland) is a plain, painfully shy woman whose emotionally detached father (Ralph Richardson) makes no secret of his disappointment in her. When she meets the charming Morris Townsend (Montgomery Clift), she immediately is taken by the attention that he lavishes upon her, attention she so desperately seeks from her father. Catherine falls madly in love with Morris and they plan to marry.
The film opens with Gustave Flaubert (James Mason) in court to defend his novel, which has been accused of being a "disgrace to France and an insult to womanhood". In order to keep it from being banned, Flaubert tells the story of Madame Bovary from his perspective.
Dr. Stewart McIver (Richard Widmark) is now in charge of a psychiatric facility, one run for many years by medical director Dr. Douglas Devanal (Charles Boyer).
French painter Michel Marnet (Charles Boyer) meets American singer Terry McKay (Irene Dunne) aboard a liner crossing the Atlantic Ocean. They are both already engaged, he to heiress Lois Clarke (Astrid Allwyn), she to Kenneth Bradley (Lee Bowman). They begin to flirt and to eat dinner together on the ship, but his notoriety and popularity on the ship make them conscious that others are watching. Eventually, they decide that they should eat separately and not associate with each other. At a stop at Madeira, they visit Michel's grandmother Janou (Maria Ouspenskaya), who approves of Terry and wants Michel to settle down.
Ruby Corey (Jennifer Jones), a poor backwoods girl living in the small North Carolina town of Braddock, is still in love with Boake Tackman (Charlton Heston). During high school, Ruby had rebuffed his aggressive advances, and was taken in for a couple of years by a kind wealthy businessman and his wife, who protected her and taught her the skills a lady would need. She moved back home when her father needed her help. Boake's family used to be wealthy, but after generations of profligacy all he has left is the land he has had drained and farmed. He starts a relationship with her but plans to marry a local woman with a rich family. When she hears the news, Ruby marries her former benefactor, Mr. Jim Gentry (Karl Malden), whose invalid wife had recently died, despite not loving him.
Rosa Moline is the neglected wife of a small-town Wisconsin doctor. She grows bored and becomes infatuated with a visiting Chicago businessman. She extorts money from her husband's patients and uses the cash to flee to Chicago, but the businessman does not welcome her. She returns home and becomes pregnant by her husband. The businessman has a change of heart and follows her to Wisconsin. He wants her back, but not her baby, so she attempts to abort by throwing herself down a hill, gets peritonitis and dies.
Italian aristocrat Angela Chiaromonte (Helen Hayes) spurns the potential husband chosen by her father (Lewis Stone) in favor of Giovanni Severi (Clark Gable), a handsome army lieutenant. When her lover is reported killed in World War I, Hayes renounces the world to become a nun. After she takes her vows, the lieutenant shows up very much alive. He implores her to give up the order, but she refuses. The lieutenant is later injured in a bombing raid; he dies, with Angela lovingly at his side.
Jessie Cassidy yearns to escape the squalor of her family's Lower East Side apartment. Hoping to move up in life, she convinces her boyfriend, Eddie Miller, to marry her. At their wedding reception self-made shipping tycoon John L. Hennessey sees the couple and buys them a bottle of champagne. Eddie tries to impress John, but Jessie impresses him more. Eddie takes Jessie to a nice apartment, then tells her that she can give up her job as a shopgirl to work in the chorus of a Broadway show, just until he gets a break. Several months later, Jessie is still in love, despite her friend Beryl Lee's warnings that Eddie is good-for-nothing. Hennessey throws a party for the cast of the Broadway show and Eddie convinces the reluctant Jessie to go. Hennessey, who has been giving parties only on the pretext of seeing Jessie, makes a pass at her, which she rebukes with a slap. Even more enamoured with her after this, he doesn't hesitate to loan her a hundred dollars after she and Eddie are kicked out of their apartment. As it turns out, the apartment belonged to other people and Eddie is arrested for bookmaking. Eddie, aware of Hennessey's love for Jessie, suggests that she divorce him, marry Hennessey, then divorce Hennessey for a large settlement. Finally seeing what kind of man Eddie is, Jessie leaves him. Some months later, she returns the money to Hennessey and they start to see each other. She promises to marry him, even though he knows she doesn't love him. They later plan a European trip. Eddie goes to Jessie and warns her to carry through his idea, but when Hennessey arrives, he throws Eddie out, even though he does not know the real purpose of his visit. After they marry, Jessie realizes that she loves Hennessey and is completely happy in their honeymoon cottage in Ireland. They soon receive a cablegram from Hennessey's assistant Briggs, advising them that labor unrest necessitates their return to the United States. While Hennessey goes to his men, hoping that they will stop their strike and save their company, Jessie confronts Eddie. He tries to blackmail her, but she says that she will leave Hennessey and flee before seeing him hurt. Just before she is about to leave him, however, Hennessey comes home and Jessie lies that she never loved him. Eddie then walks in and announces that Hennessey is now broke and "in the gutter" just like him. He also tells Hennessey about the plan for Jessie to marry and divorce him for money. Eddie then leaves and Hennessey refuses to listen to Jessie's word that she loves him. Later, however, she convinces him that she will stay by his side no matter what and that the money from the sale of her jewels will give them a new start.
Andy "Champ" Purcell (Wallace Beery) is the former world heavyweight champion, now down on his luck and living in squalid conditions with his eight-year-old son "Dink" in Tijuana, Mexico. Champ attempts to train and to convince promoters to set up a fight for him, but his efforts are consistently stymied by his alcoholism. Dink is repeatedly disappointed and let down by his father's irresponsible actions and frequent broken promises to quit drinking, but his utter devotion to his father nonetheless never wavers.
Min, a young Korean boy, moves to Japan with his father, who is a potter. One day at a local shrine, Min meets Nanae, a beautiful local girl and aspiring painter. He falls in love at first sight. She is a student at his new school, and their friendship develops despite their cultural and language differences. However, Min's grandmother suddenly falls ill, and Min returns to Korea without having a chance to explain to Nanae. While he is gone, Nanae is forced to move away to protect her and her sister from their mother's violent boyfriend. Before Min and Nanae separate, Nanae gives Min an amulet pouch with a letter inside. She tells him to open it later, and so he doesn't open it before he goes to see his grandmother. Min's grandmother notices it in his pocket and assumes that it is a present for her from Japan; not wanting to disappoint his grandmother, Min gives away the amulet pouch. When Min's grandmother eventually recovers, he returns to Japan only to find that Nanae is gone.
Chris Christofferson (George F. Marion), the alcoholic skipper of a coal barge in New York, receives a letter from his estranged twenty-year-old daughter Anna "Christie" Christofferson (Greta Garbo), telling him that she'll be leaving Minnesota to stay with him. Chris left Anna to be raised by relatives on a St. Paul farm 15 years before, and hasn't seen her since.
Stella Dallas (Belle Bennett), a small town girl who is devastated by her father's death and quickly marries the upper class Stephen Dallas (Ronald Colman), with whom she has nothing in common. After the birth of a daughter, Laurel (Lois Moran), the Dallases go their separate ways.