Pierre suffers from amnesia after a war-time accident in which he might have killed a young Vietnamese girl while crash-landing his stricken plane. His nurse, Madeleine, lives with him in a low-key but potentially romantic relationship. When Pierre sees Cybèle, a young girl in distress as her obviously loveless father is dropping her off at an orphanage, he befriends her. Each of the two is lonely, childlike, and in need of a supportive friend. Eventually, he pretends to be the girl's father, which allows her to escape the locked orphanage for a day, and he shares every one of his Sundays with her for months.