In the south of France, Marc, married with children, leads a comfortable existence. A real estate agent, he one day meets by chance during a property sale a spellbindingly charming woman whose face is familiar. He thinks he recognizes Cathy, a girl he loved when he was twelve years old and they both lived in Algeria, ravaged by the war of independence. After a night of love, the young woman disappears. As the days go by, Marc is overcome by doubt: who is this woman, who claims to be Cathy, really? An investigation begins.