London 1940. Whip-smart librarian Peggy Sparks is determined to make sure her beloved brother Joe returns home from the frontline to their mother and grandmother. So when she is offered a once-in-a-lifetime job at the heart of the war effort, Peggy jumps at the prospect of making a real contribution to her country. But when she finds herself working under the fanciful socialite Lady Marigold Cecily, Peggy discovers that those around her are more keen on dancing at the Café de Paris than on ending the war. Writing accounts of her daily life is the only thing keeping Peggy's hopes alive. Then, after she finds her inner-most thoughts accidentally published by he Ministry of Information, Peggy realises she needs Marigold's help to save her job, and to bring her brother home ...