Henry, a civil servant, suspects that his wife Sarah is having an affair, and asks his writer friend Maurice to contact a private investigator on his behalf.  Maurice has a secret, however: back in the turbulent times of the London Blitz he was once Sarah's lover, and is equally keen to find out whether she was unfaithful to him too, as she had suddenly and without explanation broken off their affair.
In a series of flashbacks the play examines the obsessions, jealousy and discernments in the relationships between its three central characters.