Jean Pargetter, the head of a secretarial agency, is baffled when her daughter, Judith, goes out with one of their clients, Lionel Hardcastle. The two meet and realize that they were once young lovers separated during the Korean War.
Jean sends Sandy to Lionel's hotel to assist him with his book revisions however when Sandy gets to the hotel she is informed that Lionel has checked out. After a charade of confusions, Lionel's publisher, Alistair, invites him to a party and Lionel brings Jean along.
Lionel and Jean spend the day at an old country town they used to visit frequently in their youth. Walking through the town they find that many things have changed but they manage to encounter old spots and some treasured memories.
Jean and Judy decide to pay Lionel a surprise visit while he lectures at a conference in Norwich. The surprise is not a very welcome one and Jean finds Lionel staying with another woman. As Alistair begins to show interest in Jean rather than in Judy, a battle of the sexes, and ages, erupts.
After their visit to Norwich, it has become quite clear that Alistair is infatuated with Jean, not Judy. Refusing to believe this and at the same time flattered, Jean feels it's only right to get back at Lionel after what happened at the lecture. Then, after making Judy feel better about herself, Lionel discovers Jean's not the only one being sought after by the younger generation.
Realizing how absurd it is that Judy and Alistair are attracted to Jean and Lionel instead of each other, the elders plan a picnic for the four of them in the hope that Judy and Alistair will realize they're meant to be together.