Just out of prison, ex-con Ugo Piazza meets his former employer, a psychopathic gangster Rocco who enjoys sick violence and torture. Both the gangsters and the police believe Ugo has hidden $300,000 that should have gone to an American drug syndicate boss. Caliber 9 is the first part in Di Leo's "Milieu" Trilogy of poliziotteschi films. It was followed by "The Italian Connection" (1972) and "The Boss" (1973).
Tourists take a boat to a remote island, where they find that most of the people have disappeared, and something is stalking them. They find a hidden room in the big mansion on a hill, and an ancient diary, which gives them clues to the source of the terror.
When a shipment of heroin disappears between Italy and New York, a small-time pimp in Milan is framed for the theft. Two professional hitmen are dispatched from New York to find him, but the real thieves want to get rid of him before the New York killers get to him to eliminate any chance of them finding out he's the wrong man.
