In New York City during the 1940s, a powerful Italian-American crime family is headed by the patriarch, Don Vito Corleone. The Corleone family is immersed in a network of business and political ties, underpinned by loyalty and a code of honor. The family deals in various illicit enterprises, while maintaining legitimate front businesses. The Don’s influence stretches far and wide, granting favors in return for future obedience. During his daughter's wedding, Don Corleone hears requests from his connections, displaying the reach of his power and the loyalty he commands. However, the shifting dynamics of the underworld and the rise of the drug trade present new challenges for the Corleone family.

As the older don navigates the changing landscape, his three sons – hotheaded Sonny, weak-willed Fredo, and war hero Michael – each deal with the family business in their own way. After an attempted assassination leaves the Don incapacitated, a reluctant Michael, previously uninvolved with the family's criminal activities, finds himself drawn into the family's cycle of violence and retaliation. His transformation begins as he steps up to shield his family from the brewing gang war, which threatens not only the family’s control but their very survival. The family's unity and legacy rest on Michael's shoulders as he maneuvers through a treacherous realm of deceit, betrayal, and an inevitable descent into darkness.