Jo Armitage stands at the window of her luxurious London townhouse. She seems listless and melancholy, refusing to pick up the ringing telephone or leave the house, despite the fact she is dressed in outdoor clothes. Her husband Jake tries unsuccessfully to cheer her up with a flippant remark.

The past: a very different Jo, energetic, happy and surrounded by her large brood of children. Jake and Jo meet for the first time, while Jo is married to another man. Over time, the couple's relationship grows, and they win the blessings of theirdisapproving parents and move into a new house together with Jo's 5 children from her previous two marriages. The first note of marital discord is struck by the arrival of a young woman called Philpot, who is full of praise for Jake. Jo suspects Jake of having an affair with her. After Jo confronts him, he admits that he kissed her once but nothing more.

The present. Jo finally departs from the house and makes her way to Harrods, the department store. She wanders the shop floors aimlessly but then begins suddenly to weep uncontrollably. She is escorted home and goes upstairs to bed, but she still overhears Jake being less than sympathetic about her emotional collapse in conversation with the doctor. Jake also expresses puzzlement over his wife's desire to keep producing children. Shortly afterwards, Jake goes to Morocco on location for a film. While he is away, Jo visits a psychiatrist, who quizzes her about her 'incessant reproduction', and has an unpleasant experience at the hairdressers when a woman verbally attacks her without provocation. When Jake returns from Morocco, Jo is pleased to see him and their relationship returns to an idyllic state. However, Jake is impatient with the children and their noisy activities. Jo suggests throwing a party for all the film people Jake worked with in Morocco. The party is very busy. The last guests to leave are Beth Conway, a starlet, and her husband Bob. Bob makes some rather cryptic remarks about what happened on location.

Jo and Jake make plans to move to a new house, a converted windmill in the countryside. They seem very happy and close. Jo's father falls ill and Jo is at his side when he dies. She reveals to her mother that she is pregnant again - news which her mother greets with dismay, as does Jake. He persuades Jo to think about an abortion and she agrees to it. While she is in hospital, she also has a sterilisation operation. Jo is initially euphoric about her liberation from childbearing and about the immanent move to the windmill. When she comes home from hospital, she is surprised to receive a call from Bob Conway asking to meet up. Bob reveals that Jake has been having an affair with Beth, and suggests that Jake persuaded Jo to terminate her pregnancy so he would be free to carry on seeing Beth. Jo is devastated and she and Jake have a vicious argument, in which he admits serial infidelity. Later, to make matters worse, Bob tells her that Beth is pregnant with Jake's child. On hearing the news, Jo physically attacks her husband. She subsequently goes off to sleep with her ex-husband.

Jake's father dies and Jo goes to the funeral, but her attempts to comfort her husband are rejected. She retreats to the windmill and spends several days and nights in quiet contemplation. This reverie is interrupted by the arrival of Jake and all the children, who come to 'rescue' her. There is a tentative reconciliation between Jake and Jo, who, in spite of all the problems in their relationship, still love each other and share a strong bond.