Occupied France. A young woman is shoved into a car by Germans, then loaded into a boxcar... At the Bussières station, a railway worker, Julien, hears voices inside one of the sealed boxcars of the stopped train. A note slips through a crack. "I'm alive and I love you. Sarah." Julien visits the address on the note and finds a family of Hungarian Jews: two grandparents, and Sarah's son Thibaud, age 4. Julien offers to help with forged papers. They give him Sarah's diary for safekeeping. Later, when he returns, he finds the house ransacked, the grandparents gone. Julien takes Thibaud home. His girlfriend Lucie senses something is wrong. She's right; Julien has fallen for the personality he finds in Sarah's diary...