In the continuing saga of the Corleone crime family, a young Vito Corleone grows up in Sicily and in 1910s New York. In the 1950s, Michael Corleone attempts to expand the family business into Las Vegas, Hollywood and Cuba.

At the height of the Vietnam war, Captain Benjamin Willard is sent on a dangerous mission that, officially, "does not exist, nor will it ever exist." His goal is to locate - and eliminate - a mysterious Green Beret Colonel named Walter Kurtz, who has been leading his personal army on illegal guerrilla missions into enemy territory.

In the midst of trying to legitimize his business dealings in 1979 New York and Italy, aging mafia don, Michael Corleone seeks forgiveness for his sins while taking a young protege under his wing.