Caroline is twenty-two, with a promising stage career. Then she meets Michael Knowles, a successful middle-aged surgeon, and her career slips into second place beside brief meetings, midnight trysts and the welcome anonymity of foreign cities, as they seek to evade the shadow of Mercedes, Michael's estranged wife. London of the 1930s gives way to the Blitz and the pain of separation, but the intensity of wartime does nothing to deflect Caroline's obsession with the three-cornered relationship. In America, some years later, she meets Mercedes, the wife, for the first time. Discovering an unexpected bond with her, Caroline begins to comprehend her own misinterpretation of the past...