Lucie and Lucien, both in their mid-twenties, have been living together for many years. Lucie sales bath suits on the beaches of Marseilles. Lucien, while he was taking the French police academy entrance exam, has been selected as secret agent. To hide his new position, even to his closest family and friends, he must acts as a dilettante and a hedonist. His first test : a young unexperienced beauty, Jennifer, who thinks he is the perfect man for taking care of her sensual initiation. As for Lucy, she's concerned not only by the fact that Lucien has suddenly become a dilettante but also by a sensual recurring dream with someone else which wakes her up each night. Following the advice of a renewed psychologist, she wants to create a more sincere relationship with Lucien by telling all the truth.