After marrying the boss' daughter, a workingman begins to doubt his abilities.

After 10 years of marriage to Susan, the daughter of wealthy millowner Abe Brown, Joe Lampton continues to be in disfavor because of his lower-class origins. Forced to wed Susan before she gave birth to her first child, Joe has used his ambition to raise himself to a senior position in his father-in-law's company, but his growing distress at his marriage and his seeming incompetence at his job have embittered him. His attitude remains unchanged even after he has run successfully in a local election as a Conservative. He is more concerned about losing his chance for promotion when Brown, contrary to Joe's advice, decides to merge his company with another one. Joe is also distressed because he is unable to put through his plans for slum clearance, since Brown is interested in more profitable business plans. Joe sees his private life ruined when he finds his best friend, Mark, in bed with Susan. Though she claims that she feels nothing toward Mark, Joe hurries to London to stay with his mistress, Norah Hauxley, a television announcer whom he met while running for public office. After a brief romantic fling, he becomes dissatisfied with Norah and with himself because of his lack of education and his inability to find a satisfying job. Disillusioned, he meets with Susan, who still loves him, in London; and he decides that he will go back to Warley, where he will be made chairman of the board, succeeding Brown when he retires.