Alfredo Berlinghieri (de Niro) and Olmo Dalco (Depardieu) are born at the same day in 1901, but belong to opposite ends of the social spectrum. Alfredo is the son of a rich landowner, while Olmo is a misbegotten peasant son. As Alfredo is somewhat rebellious and despises the falseness of his family, in particular his father, he befriends Olmo, who is brought up as a socialist.
After World War I, their friendship (with slightly homoerotic overtones) continues, but slowly the rise of the fascists as embodied by the sadistic Attila (Donald Sutherland) separates them. Alfredo chooses the side of Fascism, while Olmo fights for the communists.
Due to the considerable length of the movie of originally about six hours and several scenes in it that were deemed too graphic in some countries, a few shorter cuts exist. However, in the opinion of most reviewers the censored scenes are fairly important in understanding the plot of the movie as well as the Italian countryside life that it portrays.