June, 1940. When the house where Pierre lives with his wife Madgeleine and their son Charles is commandeered by the Wermacht, a strange cohabitation begins. On the one side, the French family with their two servants, Louise and Léa, and the beautiful Jewish tutor known to all as "Mademoiselle". On the other, the German occupants : the fanatical Krantz and honest Karl... A deep friendship soon springs up between Charles and Karl, but the threat of an uncertain future hangs over their relationship. Years go by : now Karl must leave for the Russian Front. Writing to his young friend, he describes the total horror of war. As Charles secretly reads these forbidden letters, his innocence is undermined. He grows in maturity from day to day. In his last letter, Karl speaks to Charles as a man : "When you read these words, I shall be dead, and this letter will be something like the light of dead stars : a light which continues to travel through space, though its source has long since expired..."