Lionel Hardcastle, a young man in the army, and Jean Pargeter, a nurse, are madly in love until Lionel is sent away to the Korean War and, through a lost love letter, they lose touch.

Thirty-eight years later Lionel, a curmudgeonly divorcee, is writing a book about his subsequent years spent living in Kenya and Jean, a no-nonsense widow, is running a secretarial agency in London. When Lionel requires a secretary to assist him with his book revisions he unwittingly contacts Jean's agency and the pair are reunited.

Gradually, after some reluctance and hesitation on both sides, Jean and Lionel begin to rekindle their old romance. Alongside this main story a more tempestuous relationship between Jean's daughter Judith (Moira Brooker) and Lionel's publisher Alistair (Philip Bretherton) plays out.

This popular BBC sitcom draws humour from the ups and downs of unexpected romance in later life.