American Charles Wills returns to Paris, after a two-year absence, to see his daughter. He stops for a drink at a café owned by his old friend Maurice and reminisces about the days near the end of World War II: On VE Day, Charles, a reporter for The Stars and Stripes , is among the Americans celebrating in the streets with the joyous French citizens. He ducks into Maurice's café, where he encounters his friend, Claude Matine, and is introduced to American Marion Ellswirth, who has been in France throughout the war. Marion takes the men to a party thrown by her father James, a charming rascal with a talent for living beyond his means. Charles' eye is caught by Marion's beautiful, vivacious sister Helen, and the young woman stuns him with her description of the family's decadent lifestyle. Marion grows jealous as Helen flirts with Charles, and makes an appointment to meet him later. However, Helen learns about their assignation and shows up in Marion's place, and amid the victory festivities, they kiss. When Helen later comes down with a bad flu after being out in a storm, Charles visits her in the hospital, and they decide to marry. Helen wishes to stay in France, so Charles takes a job with a Paris news agency. Marion, who is still in love with Charles, soon announces her engagement to Claude. Charles and Helen marry, move in with James and have a daughter, Vicki. Charles devotes all his spare time to his writing, but after completing two novels is still unable to find a publisher. By 1950, Charles has grown despondent over his lack of success as an author, and tired of Helen's frivolous, often outlandish behavior. One night, Charles is assigned to interview socialite Lorraine Quarl, who is in Paris finalizing her most recent divorce. They spend the evening together, and when Charles returns home in the morning, Helen's lack of suspicion nettles him. Marion calls with the news that one of James's supposedly worthless oil leases, which he gave Charles and Helen as a wedding gift, has paid off. The family celebrates its newfound wealth with extravagant purchases and parties, and Charles quits his job to concentrate on his writing. Charles' third novel is also rejected, however, and he falls into a deep depression and bitterly declares himself a failure. One night, James invites Paul Lane, a suave "international tennis bum," to attend a party with them. At the party, Paul flirts with Helen, and the inebriated Charles encounters Lorraine, who is now divorcing her fifth husband. Helen asks her husband to take her home, but he insists on taking Lorraine for a drive instead. The following day, Helen treats the badly hung-over Charles coldly, despite his assurances that nothing happened between him and Lorraine. Helen admits that she joined Paul for a nightcap at his hotel and was strongly tempted to have an affair with him. She then tells Charles she is unhappy and asks to go back to America. Charles, who has been seduced by the decadence that Helen now finds unfulfilling, refuses. Instead, he takes Lorraine to Monte Carlo to compete in an automobile race. When they return to Paris, they find Helen at Maurice's café with Paul, and Charles takes a swing at him. Paul takes Helen to his hotel and declares his love for her, but makes it clear that he wishes her to stay with her husband and keep him on the side, pointing out that half the people in her social circle have such "arrangements." Disgusted, Helen walks out and returns home, but is unable to get into the house because Charles has chained the door and passed out, drunk. Helen walks through the snow to Marion and Claude's house, then collapses. Helen is hospitalized, and when the apologetic Charles visits, she asks him to take care of Vicki, and dies. Marion sues for custody of Vicki, and the grief- and guilt-stricken Charles yields without a fight, wishing only to return to America. Back in the present, Charles tells Maurice that the oil wells dried up a year before. Charles then goes to visit James, and is surprised to find him in a wheelchair, the victim of a stroke. James commends Charles on the book he has published, calling it very honest. After being reunited with his daughter, Charles tells Claude and Marion that he wants to take Vicki back with him, but Marion bitterly rejects his emotional appeal. After Charles leaves, shattered, Claude accuses Marion of still being angry that Charles chose Helen over her. Later that evening, Charles is at Maurice's café when Marion comes in and says Helen would not have wanted him to be alone. She takes him outside, where Claude and Vicki are waiting. As Claude and Marion exchange a warm glance, Charles and his daughter walk hand in hand down the boulevard.