At the dawn of World War II, Anne Guichard, a young archivist employed at the Louvre, arrives home to find her brother missing. While she works to discover his whereabouts, refugees begin flooding into Paris and German artillery fire rattles the city. Once they reach the city, the Nazis will stop at nothing to get their hands on the Louvre's art collection. Anne is quickly sent to the Castle of Chambord, where the Louvre's most precious artworks, including the Mona Lisa, are being transferred to ensure their safety. With the Germans hard on their heels, Anne frantically moves the Mona Lisa and other treasures again and again in an elaborate game of hiding and seek. As the threat to the masterpieces and her life grows closer, Anne also begins to learn the truth about her brother and the role he plays in this dangerous game.