New York socialite Caroline Ferriday, posted at the French consulate in Paris, finds her world is forever changed when Hitler’s army sets its sights on France. Kasia Kuzmerick, a Polish teenager, sees her carefree youth disappear as she is drawn deeper into her role as courier for the underground resistance.  Herta  Oberheuser,  a young German doctor, answers an ad for a government medical position and finds herself trapped in a male-dominated realm of Nazi power. The lives of these three women are set on a collision course when Kasia is sent to Ravensbrück, the notorious Nazi concentration camp for women.