Gaston is weary of the conventions of society. He is a rich playboy and is the scion of a wealthy Parisian family who wants to find emotional refuge from the superficial lifestyle of upper class Parisian 1900s society. He seeks refuge with the former mistress of his uncle and her outgoing, tomboy granddaughter, Gigi. She is a youthful courtesan-in-training. When Gaston becomes aware that Gigi has matured into a woman, her grandmother and aunt urge the pair to act out their roles. But a surprise twist happens when the platonic relationship turns into something more.