Renée Le Roux runs the Palais de la Méditerranée, France's finest casino. But the establishment is being ruined by mismanagement and assailed by the competition. Her enemy Jean-Dominique Fratoni is determined to buy the Palais, but Renée Le Roux refuses to yield. Maurice Agnelet, an ambitious young lawyer, offers his help. He soon gains the trust of the Le Roux family and becomes both advisor to the casino, whose management he dreams of taking over, and lawyer to Renée Le Roux's daughter Agnès.