Jean, an elderly Jewish man, pores over the diary of his sister Sarah written during the German occupation of France in 1942. Sarah is young, beautiful and in love. The object of her affection is Hans, a German officer pressured into joining the SS by his overbearing father. Hans rejects the Nazi ideology and secretly provides false papers to Jews. To avoid persecution, Sarah changes her name to Louise Berger and hides in the safe house of Huguette, a cabaret singer. Strangers in peril pass through the safe house under the watchful eye of Huguette's mother Margot, struck mute since the death of her son. Despite the risk, Hans visits Louise in the safe house and, hidden from the world, their precarious relationnship blooms. The arrival of Michel, a wanted French Resistance fighter, shatters the calm of the safe house. The volatile ideology of the outside world creeps in to this utopia, and soon the safe house cannot protect the young lovers and they are forced to flee. This causes Jean to intervene, with dramatic consequences. The conflict has forged an impossible love, with a purity that transcends the animosity of war.