Like every weekend, nineteen-year-old student Rachel comes to the home of Stéphane Mancini,a forty-odd man to baby-sit his two-year-old baby Hugo. When Stéphane, who lives alone with Hugo after splitting up with his wife, has gone out for the night, Christine takes advantage of it to invite her good friend Christine. As Hugo is asleep they start exploring the apartment and have fun trying on Stéphane's ex-wife's clothes. Two of their male friends arrive and are invited to join the two girls. But suddenly Stéphane comes back, earlier than initially planned. He kicks all the gang out, except Rachel who is wearing his ex-wife's lady's suit...