Following the bloody climax of the previous film, A Better Tomorrow -- again directed by John Woo -- opens with Sung Chi-hi (spelled Tse-ho in the first film though still played by Ti Lung) getting released from jail on the condition that he rat out his gangland associate and a shipyard owner, Lung (Dean Shek). Chi-ti's younger brother, a young cop named Chi-kit (Leslie Cheung), is working undercover on the case and has already gotten into the gangster's good graces by dating his daughter, Peggy (Regina Kent). Fearing that he might put his brother's life in danger, Chi-hi cooperates with the cops. Meanwhile, Lung comes to believe that he is responsible for the death of a competitor and flees to New York. There he promptly goes crazy while under the care of Ken (Chow Yun-fat), the twin brother of the sunglass and trench coat-sporting Mark who died in the previous film. During a gun battle with the Mafia who tried to blackmail the exiled crime boss, Lung miraculously regains his sanity. Together he and Ken return to Hong Kong to settle a few scores. This film's onscreen mayhem was almost matched offscreen. Director John Woo and producer Tsui Hark had radically different views of how the film ought to progress. As a result, Hark reportedly recut the film without Woo's consent, ending a long-time professional relationship between the two filmmakers.
by Jonathan Crow synopsis