Sometimes, the deadliest enemy lies within. It is 1942, and war is raging in Europe. Monika Ritter is in New York with her husband, Michael. Haunted by memories of her childhood in Germany and her father’s death at the hands of the Nazis, she longs to do her bit against Hitler’s rampaging armies. When Michael joins the new Army Air Force as a bomber pilot, Monika takes advantage of an invitation she receives to join the OSS, a fledgling group of spies with the mission to turn the war by gathering the most vital asset of all—information.

Paris, 1940 German tanks rumble through the streets of Paris, forcing frightened citizens to flee. But not everyone has the luxury to leave. Camille Lacroix, a chambermaid at the world-famous Hôtel Ritz, must stay to support her family back home in Brittany. Desperate to earn money, Camille also acts as a lady’s maid for longtime guest Vivian Miller, a glamorous American widow—and a Nazi sympathizer. Despite her distrust of the woman, Camille turns to Vivian when her friend Rachel Berman needs help getting out of Paris. It’s then that Camille discovers that Vivian is not what she seems.

Teddy’s job is to process visa applications, and by 1939, refugees from Nazi-conquered Poland, Austria, and other countries are desperate to secure safe passage to America. As Hitler sweeps through France, Belgium, Luxembourg, Denmark, and Holland, the screws tighten and law after virulent law is passed to threaten the lives, indeed the very existence of the Jewish people. When Teddy and his girlfriend Sara are introduced to an orphaned young girl named Katy, who has been abandoned on the grounds of a nursery school, they agree to adopt her.

A broken family. A new opportunity in a country on the precipice of unspeakable evil. November 1932. Seamus Ritter, a widower with four children, returns from riding the rails in an America crippled by the great depression. Realizing that his homecoming will not be how he envisioned it, and in a desperate attempt to make amends with his 16-year-old daughter, Maureen, Seamus accepts an invitation to come and work for his long-lost uncle in Berlin. With little other choice, Seamus takes the ship to Germany with his family.

On a November day in 1940, Adam Paskow becomes a prisoner in the Warsaw Ghetto, where the Jews of the city are cut off from their former lives and held captive by Nazi guards to await an uncertain fate. Weeks later, he is approached by a mysterious figure with a surprising request: Would he join a secret group of archivists working to preserve the truth of what is happening inside these walls? Adam agrees and begins taking testimonies from his students, friends, and neighbors.