Inspector Betti (Maurizio Merli) is transferred to Naples and immediately after his arrival receives a warm welcome from The Commandante (Barry Sullivan), the city's crime lord. Betti then goes on a personal mission against corruption and organized crime, and tries to force the syndicate out of town with any means necessary.

When a crime boss sends out his thugs to terrorize an entire city, they do whatever they want, which includes anything from petty theft to robbing the police station in broad daylight. Napoli spara! (internationally released as Weapons of Death and Naples shoots) is a "poliziottesco" film directed by Mario Caiano in 1977. It is an unofficial sequel of Napoli violenta, of which reprises the character of Gennarino (still played by Massimo Deda).

A humble car mechanic decides to give his son, who has brought home an excellent school report, a golden watch. Unfortunately the jewellery shop where they go and buy the watch is held up and the boy gets killed. The man spends the rest of the movie trying to take his revenge...