New York, present day: On a whim, Juno Lambert buys a 1931 Underwood typewriter that once belonged to celebrated journalist Cordelia Capel. Within its case she discovers an unfinished novel, igniting a transatlantic journey to fill the gaps in the story of Cordelia and her sister and the secret that lies between them.Europe, 1936: Cordelia's socialite sister Irene marries a German industrialist who whisks her away to Berlin. Cordelia, feistier and more intellectual than Irene, gets a job at a newspaper in Paris, pursuing the journalism career she cherishes. As politics begin to boil in Europe, the sisters exchange letters and Cordelia discovers that Irene's husband is a Nazi sympathizer. With increasing desperation, Cordelia writes to her beloved sister, but as life in Nazi Germany darkens, Irene no longer dares admit what her existence is truly like. Knowing that their letters cannot tell the whole story, Cordelia decides to fill in the blanks by sitting down with her Underwood and writing the truth.When Juno reads the unfinished novel, she resolves to uncover the secret that continued to divide the sisters amid the turmoil of love, espionage, and war. In this vivid portrait of Nazi Berlin, from its high society to its devastating fall, Jane Thynne examines the truths we sometimes dare not tell ourselves.