In New York's Chinatown, Chinese gangs are everywhere. Chinese police officer Chen Li (played by Chow Yun-fat) has made great achievements and has been promoted step by step by colluding with gang forces and balancing the interests of spies from various gangs. However, all this peace was suddenly broken. A new gang of gang members from Fujian came to Chinatown and called themselves the "Dragon Gang". They started a fierce battle for territory with the old gangs, which became more and more intense, and even Chen Li could not come forward to settle it. This situation attracted the attention of the New York Police Department, and they sent a young and promising police officer Danny (played by Mark Wahlberg) to investigate the gangs in Chinatown. When the gangs of various factions failed to bribe the honest Danny, they decided to get rid of him. Chen Li, who was in a dilemma, would watch his companions being killed?