In a snowball fight between schoolboys the handsome Dargelos hits the chest of Paul, who drops unconscious to the ground. Paul has a deep affection for Dargelos, and later denies that there was a stone in the snowball that hit him. Back home Paul's sister Elisabeth takes care of him. The teenage siblings live together in one room, where they have developed several private games. Paul's schoolmate Gérard is secretly enamored of Elisabeth, and often stays with them.