Two sisters live in France at the beginning of World War II. The older sister, Vianne Mauriac, says goodbye to her husband, who's heading off to fight in the war. She and her daughter become prisoners in their own home after it's requisitioned by German forces, and Vianne is faced with making impossible choices to save her family. Her younger sister, Isabelle, is an 18-year-old girl who falls for a young man who eventually betrays her. She then joins the Resistance and begins risking her life to save others.