In the first time of the Tirology, small-tiem gangster Ugo Piazza has just been released from prison. He tries to convince the police, the mafia, and his one-time associate Rocco, a sadistic hoodlum who enjoys sick violence and torture that he wants to go straight, but everyone believes that he has $300,000 of stolen money hidden somewhere.

Caliber 9's stylized violence, fast-paced action sequence, tight editing and plot twists prefigure the work of Quentin Tarantino and John Woo. The film also features a notable score by Luis Bacalov and the stunning Barbara Bouchet as Ugo's go-go dancing girlfriend.