It is summer in 1920s England and a group of friends are enjoying one of many weekends at Mayfield, the Wyndham family's country home. Amid the gaiety of punting on the river, tea on the lawn and lavish parties, a love triangle emerges: Caroline, thought by everyone to be heading for engagement to George, surprises everyone by agreeing to a Philip's sudden proposal, leaving George distraught. Six months later Caroline and Philip marry but it is not long before she realises that people are not always as they appear and that Philip has been hiding a secret . . . As the years slip by Caroline's marriage is plagued by fears that she made a horrible mistake and a tragic turn of events takes her life down an unexpected path.