Rosemary Hoyt, a beautiful eighteen-year-old movie starlet, on vacation with her mother, arrives at a rather deserted portion of the French Riviera. There, Rosemary meets Dick Diver, a handsome American psychologist in his thirties with whom she instantly falls in love. Dick and his wife, Nicole, are exemplars of grace and sophistication, and move among a social set of similarly extraordinary people. Rosemary becomes part of this world, and in the gay times that follow, Dick begins to reciprocate Rosemary's feelings for him. Everything goes splendidly until, after an alcoholic friend of the Divers accidentally kills a man, Rosemary discovers Dick comforting Nicole, who has had a mental breakdown.