As war rages across Europe, one young woman faces an impossible choice. Will she save her country... or the man she loves? It is the late 1930s. In London, socialite Rosamund Hanbury is determined to give up the parties and social sets of which she is a prominent member to join the war effort, along with scores of other young women. After a stint at Bletchley Park and as one of the Air Transport Auxiliary's 'Atagirls', Rosamund is recruited by the Special Operations Executive under the code name 'The Scarlet Nightingale', and eventually moved in secret to France. There she falls under the charm of Count Thierry Foustier, a gallant Frenchman with a taste for danger and women. But in the high-stakes role of secret agent Rosamund can't trust anyone, for if her true identity is revealed, she will be killed. As the peril of her top-secret operation mounts, Rosamund will be drawn into the very heart of the war, where her love and her loyalty will be put to a test more devastating than she could ever imagine. Set between wartime London and Paris, this is a thrilling story of love, danger and betrayal from bestselling novelist Alan Titchmarsh.