Yorkshire, the early 1950s. Joe Lampton moves from the poor town of Dufdon to the wealthy town of Warnley to take a job in the Treasurer's Department.

A colleague, Charles, is assigned to look after him. Joe tells him about Dufdon and about his experiences as a prisoner of war while serving in the RAF. Although proud of his humble origins, he is fiercely ambitious and sees Warnley as an opportunity in terms of both career and women.

Charles takes him to an amateur theatrical production. Joe admires two women, an older Frenchwoman called Alice Aisgill and Susan Brown, the young daughter of a local industrialist. He makes his interest clear to Susan but is mocked by her boyfriend, Jack Wales, an RAF officer and escaped Prisoner of War, who pulls rank.

Joe joins the dramatic society to pursue his ambitions. He feels defensive about his class background and tells Alice of his frustrations and aspirations. She tells him about her unhappy marriage to Aisgill.

Joe fixes up a date with Susan and tells her that his parents were killed in an air raid. They are interrupted by Wales who continues his snobbish sneering. Joe's boss warns him away from Susan and tells him to stick to his own class.

He meets Alice. She tells him to drive to a country beauty spot where they make love.

Joe is offered a good job in Dufdon. He goes for an interview and sees his old home, now a bombsite. No one in the street recognises him. He visits his Uncle and Aunt and tells them about Warnley life and Susan. They are concerned that he seems only interested in her money. He has the interview but when he discovers that Brown had set it up, he leaves.

He finds out that Susan has been sent to the South of France for the summer. He cools towards her and embarks on a passionate affair with Alice. They fall in love and meet regularly at her friend Elspeth's flat. After a bitter row, in which she mocks his sexism and defensiveness and he mocks her age, they split up.

At a civic ball, Joe sees Susan with her family. They are snobbish towards him but she tells him she loves him. He says he loves her. Meeting later he persuades her to make love. After sex she tells him that they really belong to each other now.

Joe feels unhappy. He arranges to meet Alice and fixes up a holiday at a remote cottage. They have an idyllic time together, although Alice is fearful of what might happen. Joe reassures her that he wants to be with her and she agrees to seek a divorce.

Aisgill threatens to ruin Joe if he tries to bring a divorce case. Brown meets Joe and tests him by trying to pay him off before revealing that Susan is pregnant. He will arrange a marriage between them and set him up in his business if he stops seeing Alice.

Against Susan's wishes Joe visits Alice to explain. She is devastated and goes drinking on her own, driving home.

Joe goes to his office where everyone congratulates him on his wedding. He overhears some of them mention that Alice has been killed in a car accident while drunk. Full of remorse, he goes on a drinking binge in the poor part of town. He argues over a girl with a group of toughs who tell him to stick to his own class. Later they beat him up and dump him in the street. Charles finds him and hauls him back for the wedding.

Joe and Susan get married. He appears dazed throughout the service. She sees him crying and mistakes it for love for her.