Cigarette smugglers in Naples run into problems with cocaine operations being set up by a rival smuggler.

Sicily, Fascist Italy, 1925. Dictator Benito Mussolini appoints Cesare Mori, a man as tough as he is honest, as the new police prefect of Palermo and entrusts him with the arduous task of putting an end to the Mafia, a sinister criminal organization that has sown terror on the island for centuries.

Joe Dallesandro plays a hungry young buck who aspires to be a career criminal. He starts out working at a warehouse for a gangster where he helps to relocate illegal contraband, and because of his ruthlessness and dependability he begins to ascend the ladder of organized crime. Of course, the more powerful he becomes, the more "Climbers" come out of the shadows to take his place.

Set in Naples at the end of the 19th century, I Guappi tells the story of a strange friendship between the powerful and charismatic Camorra boss, Don Gaetano (Fabio Testi), and one of the many scugnizzi who grew up on the streets, Nicola Bellizzi (Franco Nero). Nicola, thanks to Don Gaetano's protection, becomes first an honoured picciotto of the Camorra and then a lawyer. He tries to break away from his 'family', but falls back into a life of crime and violence.

The fast career of a young Neapolitan among contraband, gambling dens, bribes and illegality. He will upgrade its rank till the maximum level of the "Family".