After resolving a hostage crisis in a kindergarten with her partner Ada, Agent Chen Xiaohong heads to Scotland, leaving the bustling streets of Hong Kong behind for a while. Back in Hong Kong, Zeng Jian, the ruthless boss of the Rifuda Group, returns after seven years in Thailand and wastes no time in reasserting control. He targets Bin, whom he blames for helping the police corner him and force a retreat to Thailand. Bin makes a desperate attempt to shooting at Zeng Jian, but Zeng Jian’s enforcer, Miss Nishiwaki, strikes first and ends Bin’s life.
With Bin out of the picture, Zeng Jian distributes Bin’s wealth among his four loyal generals—Rong, Tiedeng, Paowangbiao, and Fatal Xiong—a move the police watch closely as they fear a new power struggle in the organization. The cops are especially intrigued by a shadowy figure known only as “Sawa Da,” a name that appears on Zeng Jian’s Thai passport and hints at an elusive mastermind pulling strings from the shadows.
Meanwhile, civilian Carrie is taken hostage at a mall by two fleeing thieves wielding machetes. Her police commissioner husband, Jin Zhiyuan—who is also the cousin of Chen Xiaohong—rescues her, though the confrontation leaves Jin badly injured. The case draws Ada back into the orbit of Zeng Jian’s operations, and Ada’s informant Mei reveals that Sawa Da will attend a party at Club Xingda that very night.
At the party, Zeng Jian seals a drug deal with Leung Ming in a warehouse setting that is scheduled for 9:00 p.m. on Friday the 13th. He also attempts to rekindle a connection with his old flame Carrie, who has moved on and introduced him to her husband Jin Zhiyuan. Ada confronts Zeng Jian at the party and publicly announces his true identity. Mei later informs Ada about the drug deal and the ensuing police raid, a confrontation that ends with Ada killing Zeng Jian’s right-hand man Wei.
The tension rises as Jin Zhiyuan falls deeper into debt through games at one of Zeng Jian’s gambling houses, prompting Zeng Jian to coerce Carrie into sex for money to erase the debt. Jin agrees to trade seized merchandise for debt erasure, triggering a violent clash between him and Carrie. Ada follows Jin to a meeting with Zeng Jian, who confesses the affair, and Jin pulls his gun. Ada intervenes, pleading with him not to shoot, but Jin is killed by Zeng Jian, and Ada is captured and forced into a heroin addiction.
Chen Xiaohong returns to duty and is informed by Director Huang that the police suspect Ada killed her cousin. Carrie attempts to intervene on Ada’s behalf but is killed by Miss Nishiwaki as Ada escapes. Mei attempts to help Ada by reuniting her with Xiaohong, but Xiaohong is reluctant to face what has happened. Mei is eventually killed by Miss Nishiwaki, heightening the peril for Ada.
With Mei gone, Ada emerges from hiding to assist Xiaohong in dismantling the gang’s remaining forces. The pair launch an assault on Zeng Jian’s residence, where he is negotiating a deal with Samak. As Zeng Jian tries to speed away to escape, Ada clings to an overhead power line, waiting for her moment. Zeng Jian fires at her, but Ada manages to lunge down, strike at him, and bring his car to a dramatic crash. The story ends with Ada dying while still hanging from the power line, having sacrificed everything to bring down the danger that defined her world.
