Norfolk seaside resort Thurnemouth is home to three retired couples, bossy Joyce and her easy-going husband Alan, ultra-conservative John and sensible Maureen and nervous Carol, who, with boring Trevor, is rebuilding the marriage after a separation.

Joyce organizes a fortieth wedding anniversary party for Carol and Trevor, inviting John and Maureen and Maureen's bibulous, wheelchair-bound mother Joan. Before setting out to the restaurant Carol confesses to Maureen and Joyce that she finds Trevor boring and plans to leave him.

The resort celebrates its history on Thurnemouth Day with Trevor dressing as Lord Nelson to cut a ribbon. Maureen takes him to get his costume, offering marital advice.

Joyce is retiring and Alan is throwing a party for her at home. Homesick for London, Maureen invites new residents Sara and Dan who have moved from the capital with their children, but the party turns out to be quite a hassle.

Maureen and John move Joan from sheltered accommodation to a care home. Maureen's brassy sister Pauline arrives to 'help' but scares the men-folk with her predatory nature.

The three couples take their usual summer holiday at the Hollingers hotel's 6os weekend. Maureen loves it, unlike Joyce, but things get worse when it appears that Alan only booked two rooms so the men are separated from the women.