In the Philippines, Officer Man [Alex Man Chi-Leung] leads his squad to bust a drug deal and traps Talung, the second in command of a counterfeiting operation run by Roy [Waise Lee Chi-Hung]. At night, Man’s junior Santos [Monsour Del Rosario] also arrests Roy’s girlfriend Yu Yung Chi [Carol Tam], but tragedy strikes when Man is killed at his mother’s birthday celebration by a hitman sent by Roy.
Meanwhile in Shenzhen, Officer Yang Lai-ching [Cynthia Khan] uncovers a drug deal and discovers the money used in the transaction is counterfeit. She is part of a joint operation between Hong Kong, Chinese, and Filipino police to root out drug dealers in the Philippines who use counterfeit cash to buy drugs in China for trafficking to Hong Kong. Yang is tasked with getting close to Yu in prison while partnering with Hong Kong inspector Lee King-tong [Lee King-tong notations refer to actor: Yuen Biao], who has spent three years undercover in the Philippines.
Back in the Philippines, Lee visits Yang in prison and the plan is set: they will pose as a married couple to get close to Yu. Yang befriends Yu after defending her from a bully, and Santos launches an arrest at a restaurant once linked to Roy’s operation, with Roy’s employee taking the fall when cocaine is found. On Valentine’s Day, Lee arrives bearing flowers and two bottles of dioxide solution intended to help Yang and Yu escape while they’re transported to the hospital. Lee then calls Santos to set up a night meet, where he faces hitmen hired by Roy who threaten Santos’s wife and daughter, until Lee arrives and saves them, taking out the attackers.
The next day, Yang and Yu follow Lee’s plan and are rescued from the ambulance. Yu leads Lee and Yang to Roy’s mansion, where one of Roy’s partners recognizes Lee as a former pimp who cheated him, and a tense confrontation reveals that Roy’s villa is bugged. Lee and Yang realize the surveillance but push ahead, building a nerve-wracking partnership under pressure. Roy hires Lee to rescue Talung from the courtroom, and Lee executes a bold ruse by posing as a bomb-disposal officer: he evacuates the court, then detonates a car used to bring Talung to prison, while a bomb-disposal vehicle disables guards escorting Talung.
Impressed, Roy assigns Lee a second mission—to assassinate Santos. Lee stages a shootout with Santos in a supermarket; they pretend to shoot at each other while Roy’s henchmen strike, killing several of Roy’s men. Yet Santos dies in the chaos, and Roy, jubilant, showers Lee with cash, which Lee throws away in anger as he drowns his sorrows with alcohol.
Roy’s boss, a formidable figure portrayed by Billy Chow Bei-Lei, sees potential in Lee and contemplates elevating him inside the gang. Roy, uneasy, pulls a gun in a tense moment until Ramos [Jerry Bailey], Roy’s partner, stops him. The two men later head to a nightclub for a deal with a client, Peter Wu [Alan Chui Chung-San], whom Lee recognizes as a criminal he has arrested before in Hong Kong. Ng [Shum Wai] is introduced as a key player in the matter, and Roy’s boss—formerly a soldier—plans to cast Lee and Yang under martial law, but Santos and his men intervene, saving the pair and turning the tide.
In the climactic showdown, Lee and Yang join Santos and a growing group of allies to take on the boss’s forces. They storm the boss’s headquarters and, after a brutal exchange, Lee ultimately defeats the boss by delivering a final, decisive strike with a bamboo spear hidden in a water hose—ending the operation and dismantling the network.
