Agatha is aware of an intensity, a powerful storm of emotion briefly awakened by a shortlived love affair with her cousin Gerald, that is entirely lacking from the successful marriage on which she is about to embark. Beautiful, young and carefully brought up, Agatha knows she is securing a perfect and luxurious future in marrying handsome John Clewer and becoming Mistress of Lyndon, and she soon becomes the perfect country house hostess. But when Gerald reappears and war in Europe disturbs the sheltered comfort of Lyndon forever, Agatha is once again haunted by the idea of a different life.