England, 1939: The Penrose sisters couldn't be more different. Skye is a daring and brash pilot, and Liberty is the one to defy her at every turn. Even if women aren't allowed in the Royal Air Force, Skye is determined to help the war effort. She's thrilled when it reunites her with her childhood soul mate, Nicholas. She's less thrilled to learn Nicholas is now engaged to an enigmatic Frenchwoman named Margaux Jourdan.

Paris, 1944: The war is nearly over, but for members of the Resistance in occupied France, it is more dangerous than ever before. Twenty-five-year-old Gabby Foucher loathes the Nazis, though as the concierge of 10 rue Royale, she does her best to avoid conflict - unlike her bolder sister Yvette, who finds trouble at every turn.

Elisabeth Eidenbenz left Switzerland in 1937 to aid children orphaned during the Spanish Civil War. Now, her work has led her to France, where she's determined to provide expectant mothers and their unborn children a refuge amid one of the worst humanitarian crises of the twentieth century. Desperate to escape the invasion of Franco's Fascist troops, Isabel Dueñas becomes one of many Spanish patriots fleeing their country. She leaves behind her husband as he fights for democracy, and she seeks asylum in a refugee camp across the border in France.

New York, 1898. The only thing more shocking than Arthur Stanhope III’s unexpected death is the revelation that his will bestows his company—and most of the vast fortune that goes with it—to the nearest male heir, leaving his mother, wife, and daughter nearly impoverished. His widow, Sylvia, quickly realizes she must set aside her grief to ensure their daughter, Adelaide, is launched into society as soon as the appropriate mourning period passes.

London, 1938: The bookstore just doesn’t feel the same to Gertie Bingham ever since the death of her beloved husband Harry. Bingham Books was a dream they shared together, and without Harry, Gertie wonders if it’s time to take her faithful old lab, Hemingway, and retire to the seaside. But fate has other plans for Gertie. In Germany, Hitler is on the rise, and Jewish families are making the heart-wrenching decision to send their children away from the growing turmoil. After a nudge from her dear friend Charles, Gertie decides to take in one of these refugees.