After the death of his estranged father, professional rainbow-watcher Stefano finds out he has a 13-year-old half-brother, and that he must become his legal guardian to receive the inheritance.
Divorced high school PE teacher Gilberto falls in love with Margherita, unaware that she is the mother of Paolina, a student that has been sending him "I love you" notes written in every language in the world.
