When the leading lady of a low-budget musical revue sprains her ankle, the assistant stage manager is forced to understudy and perform in her place.
Antonia Lynch-Gibbon, wife of upper-crust wine dealer Martin, falls in love with her husband's best friend, noted psychiatrist Palmer Anderson. While both Palmer and Antonia would like to remain in Martin's life, he has some secrets of his own — namely, a mistress called Georgie, whom his womanizing brother also desires. All the while, Palmer's sister Honor seems to know everyone's business.
Sir Anthony Blunt, who was a Soviet agent for 25 years, is routinely questioned and gives no answers, but is knighted and works as Director of the Courtauld Institute, and presents his interrogator with a puzzle in the shape of a doubtful Titian painting. He also does art restoration work in Buckingham Palace, where he gets into an interesting conversation with HMQ.
