In 1939, curators at the Louvre nestled the world's most famous painting into a special red velvet-lined case and spirited her away to the Loire Valley. So began the biggest evacuation of art and antiquities in history. As the Germans neared Paris in 1940, the French raced to move the masterpieces still further south, then again and again during the war, crisscrossing the southwest of France. Throughout the German occupation, the Louvre's staff fought to keep the priceless treasures out of enemy hands, often risking their lives to protect the country's artistic heritage. This is the sweeping, suspenseful narrative of their battle.