Drama based on the novel by Francoise Sagan. Jean Seberg plays Cecile, the spoiled 17-year-old daughter of Raymond (David Niven), a wealthy Parisian widower vacationing in a sumptuous villa on the French Riviera. Their shallow, pleasure-seeking existence is threatened when Raymond decides to marry Cecil's straitlaced godmother, Anne (Deborah Kerr), who disapproves of the teenager's steamy summer affair with Philippe (Geoffrey Horne). To keep her carefree world from being shattered, Cecile plots to drive Anne away. But it's goodbye happiness and bonjour tristesse (hello sadness) when the plan takes an unexpected and tragic turn.