Giulia and Carlo have been happy together for three years, but Giulia's announcement that she is pregnant sends him into a secret panic. Terrified at his imminent entry into the adult world of irreversible responsibilities, Carlo finds himself tempted by a bewitching 18-year-old girl, Francesca, whom he meets by chance at a wedding. The possibility of one last youthful crazy fling before the impending prison of parenthood proves to be too attractive to resist.