Samuel is a psychoanalyst. All day long, he sees patients who express grievances, particularly rebellious teenagers who despise their parents. This has led him to have a dim view of the idea of becoming a parent. That's when his girlfriend, Mathilde, tells him she is pregnant. Terrified of having a child and being a parent, Samuel sees Mathilde's pregnancy as a nightmare. The advice of Samuel's friend, Marc, a womanizer and a bachelor, does not help Mathilde's anxiety.
On the other hand, Dominique, Marc's sister, and her husband, Georges, already have three daughters, and when they learn Dominique is pregnant for the fourth time, they take it in stride. The two couples experience the ups and downs of pregnancy and along the way, build strong knots of friendship.