Two Chinese police detectives, played by He Lin and Xia Qing, are sent to Hong Kong to collaborate with local drug enforcement authorities. The film centers on their mission to dismantle a powerful drug trafficking network operating in the city. Upon arrival, the detectives begin investigating the case, gathering intelligence, and working undercover to infiltrate the criminal organization. As they delve deeper, they face numerous challenges and dangers, including betrayal and violent confrontations with the drug cartel. The story follows their efforts to track down the key figures behind the operation, including the ruthless drug lord, portrayed by Zhang Kang'er. Through their relentless pursuit of justice, the detectives uncover the vast web of corruption and crime that threatens to destabilize Hong Kong. Ultimately, their collaboration with the Hong Kong police leads to a decisive showdown, culminating in the successful dismantling of the drug ring and the apprehension of its leaders. The film highlights the importance of cross-border cooperation in combating transnational crime.