Italy, 1977. Professor Bruschi is a retired widower who lives according to a strict routine he set for himself. An ardent old-style communist, he has always been at odds with the unconventional lifestyle led by his son and his hippieish girlfriend Stella. When their four-year-old daughter is left in his care out of the blue after the two break up, the old professor becomes a sort of father figure to the girl, growing fond of her. However he's once again challenged when Stella also arrives for a stay in his elegant villa, reclaiming custody of her daughter.

With her father on trial, 15-year-old Mignon leaves Paris to stay with her Italian relatives. The rather prim, snooty teen at first struggles to fit in with the more earthy Forbicioni family, each with their own problems. Eventually she bonds with her lovestruck little cousin Giorgio—who'll learn important life lessons over the course of his summer with Mignon.

Giuseppe Moscati, Doctor saint of Naples, was a doctor of the early twentieth century, from an aristocratic family devoted his career to serving the poor. The film focuses on the human side, partially leaving aside the spiritual part.