New York, present day: On a whim, photographer Juno Lambert buys the 1931 Underwood typewriter that once belonged to celebrated journalist Cordelia Capel. Within its case she discovers an unpublished novel, igniting a transatlantic journey to fill the gaps in the story of Cordelia and her sister's loving yet tempestuous relationship. England, 1936: Cordelia's socialite sister, Irene, marries a German man from a powerful family who whisks her away to Berlin. Cordelia remains in England to pursue the writing career she cherishes, but in the male-dominated world of journalism, she can only get hired as a typist. The sisters exchange letters as politics begin to boil in Europe and tensions come to a head when Cordelia discovers Irene's husband is a Nazi sympathizer. Does that make Irene one by proxy? With increasing desperation, Cordelia writes to Irene, seeking to understand her loyalties. But the sisters' letters don't tell the whole story. So Cordelia decides to fill in the blanks by sitting down with her Underwood and--finally--writing the truth. When Juno discovers the trove of letters the two exchanged, a vivid portrait of Berlin in the devastating years during and after the war comes into focus. In this moving novel, Jane Thynne offers an intimate glimpse into a lesser known side of World War II.