Petru is a professor of mathematics at the Polytechnic University of Bucharest and leads a carefree life. He's in an open relationship with Irina, who overlooks that he sleeps with other women from time to time. But once Irina gets pregnant, Petru is forced to change his lifestyle and grow up, even he's 42. One of his friends, who was always there for him, decides to write a book about his story.