An imprisoned murderer carries out a violent bid for control of Naples' underworld crime syndicate.
Manfred, backed by Saracen pirates, deposes the Duke of Montfort, takes over the throne and kidnapped the Duke's young son. Capt. Riccardo, the leader of a pirate band on the ship Black Hawk, sets out to defeat Manfred and his Saracens and restore the Duke to his rightful place on the throne.
Four bandits commit a robbery in a villa. The maid calls the police and Commissioner Carli immediately orders patrols to chase them.
