Sidney Lumet's drama portrays the real-life struggle of an honest cop against a corrupt system. Starring Al Pacino as NYPD officer Frank Serpico. After witnessing violent and corrupt behavior by his fellow officers, Serpico decides to expose what he has seen. Instead, he is scorned and harassed. Serpico's revelations trigger an independent investigation by the Knapp Commission, but they also make him a marked man, permanently changing his life. This is a breathtaking, suspenseful story of establishment and counter-culture.