'You come from a long line of mistakes', Guy Caulder tells his daughter Alice. 'My mother married the wrong man. Her mother did the same'. At the end of a love affair, Alice journeys to Normandy to meet Guy's mother, the grandmother she has never known. She tells her that there was one true love story in the family. In the summer of 1942, Kitty is an ATS driver stationed in Sussex. She meets Ed, a Royal Marine commando, and Larry, a liaison officer with Combined Ops. She falls instantly in love with Ed, who falls in love with her. So does Larry.