Three young men - Jacques, Pierre, and Michel - share an apartment in Paris, and have many girlfriends and parties. Once, during a party, a friend of Jacques' tells him he has a quite compromising package to deliver, and asks him if he can leave it discreetly at their place. Jacques agrees and, as he works as a steward, flies away for a one-month trip in Japan, telling Pierre and Michel about the package. Then, one of Jacques' former girlfriends drops a baby before their door, making Pierre and Michel believing it is the package they are waiting for. Their lives are then completely changed.

Marie (and her three fathers) are taking A-levels. Marie passes. She spends the summer in the country with her mother, Sylvia, who has returned from America with her Californian husband who has two sons. Marie falls in and out of love for the first time in front of her alarmed fathers, who see Marie's innocence slipping away at frightening speed, and their relationships with the two women become even more complicated.