London, 1962: Celia Duchesne longs for a career, but with no means or qualifications, she passes her time working at a dusty bookshop. The day a handsome American enters the shop, she thinks she might have found her way out of the monotony. Just as the excitement of a budding relationship engulfs her, a devastating secret draws her into the murky world of espionage. France, 1942: Nineteen-year-old Anya Moreau was dropped behind enemy lines to aid the resistance, sending messages back home to London via wireless transmitter. When she was cruelly betrayed, evidence of her legacy and the truth of her actions were buried by wartime injustices. As Celia learns more about Anya --- and her unexpected connection to the undercover agent --- she becomes increasingly aware of furious efforts to protect state secrets.