1952. Orphaned as a young child, Emma Booth was raised by her grandparents in a Lancashire village. But when she stumbles across a letter written in 1940, the revealing contents make Emma realise everything she believed is a lie - her widowed father had, before his death at Dunkirk, married again, and left Emma with a half-sister, Betty Booth. Determined to find her, Emma is drawn away from the countryside to the austere city life of post-war Liverpool. Despite the different lives the women lead, they discover common ground and get along well. And when trouble inevitably comes, Emma rises to the challenge and in doing so finds love, taking her life in a whole new direction; meanwhile, Betty has to overcome devastation before her dream can come true.