An American in Paris lives by sponging off his working friends, and throws a party using borrowed money when his rich American aunt dies, believing firmly in his horoscope.

Philippe Marcillac grew up in Sète, where he specialized in pranks of dubious taste. One day, as a teenager, he organizes a party in an abandoned villa. Philipe finds himself alone with Marie-Titite, who advises him to restart his life on a more serious footing.

Sabine Gravières, married to Edouard, the High Commissioner for Criminal Youth, has a problem: Juliette, her daughter, is not only pregnant but she also refuses to marry Claude, the young man who got her pregnant. It is fair to say that the model set by Juliette's parents is far from ideal. Aware at last of the problem, Sabine decides to try and make it up with her husband.