In the French Riviera, the spoiled and futile seventeen years old girl Cecile (Jean Seberg) is spending the summer vacation with her father, the widow playboy and bon-vivant Raymond (David Niven), and his girlfriend Elsa (Mylène Demongeot). Cecile has a serious Complex of Oedipus with her father, and they have a quite incestuous relationship. The successful designer and former friend of her mother Anne Larson (Deborah Kerr) arrives in their seaside house invited by Raymond to spend a couple of days with them, and the life of Cecile changes when Raymond proposes Anne to marry him. Full of jealousy, Cecile plots with Elsa to separate Anne from Raymond.