Plot
ICAC senior principal investigator William Luk makes a presentation at the PanAsia Convention Against Corruption (PACAC) in W City where his boss, Yu Sir, introduces him to the legal adviser of the SE Anti-corruption Association, Chief Justice of Asia Emma Pong, who plans to travel to Hong Kong next week to host a forum addressing the issue trafficking sex slaves. There, a female suicide bomber and holds Pong hostage while a group of terrorists led by Sirius and a gunfight ensues where Sirius kills the suicide bomber and Yu Sir. Luk then shoots Sirius dead while the other terrorists escape as Luk runs out of ammunition. Back in Hong Kong, the ICAC starts investigating the sex trafficking case while Luk's friend and informant, Wong Lam-luk snaps photos of senior customs inspector Kwong Yat-long discussing business with Chumook. The next day, Luk leads his squad, which include Kenny Ching, on an operation to spy on Kwong at the Kwai Tsing Container Terminals. By night time, they notice sex slaves being unloaded from one of the containers and a gunfight ensues between the ICAC and the traffickers, while Luk's friend and police inspector Lau Po-keung arrive with his squad to back the ICAC. One of the slaves, whose younger sister was killed in the gunfight, reveals to the ICAC that they were from Thailand who were forced to work in clubs in Hong Kong and at the same time, Ching finds out the fake passports found from the terminal had fake visas which can only be made by the higher ups in the Immigration Department.
Ching later confronts his younger half-brother Ching Fei-hung, a customs officer who was also present at the terminal, but Fei-hung is tight-lipped. Through investigation, the police discovers that the terrorists at the PACAC and the terminal are led by King, a former drug lord of the Golden Triangle who is on Interpol's Red Notice, while Judge Pong has been sanctioning King and freezing his assets. Since Pong will arrive in Hong Kong in three days, Yu Hung-sing, Director of Crime and Security Bureau sets up an interdepartmental task force with Luk continuing on investigations while Lau is transferred to the G4 department to protect Pong's safety in Hong Kong. It turns out King works as a mercenary for the mastermind behind the international human trafficking syndicate, Siu Cheuk-ngah. Siu orders Chumook to kill every government official that they bribed, including Kwong.
Pong arrives in Hong Kong and Lau and his squad are assigned to protect her. On the way to the forum, they were ambushed by terrorists on the freeway leading to a chase and shootout where Pong's assistant, Alice, was wounded. Lau suggests Pong to leave Hong Kong for her safety but she refuses, revealing to him that Alice was a victim of human trafficking and she insists on battling human trafficking issues. Later, Luk discovers Siu is also on Interpol's wanted list under one of his many alias and confronts Siu in the latter's company, who poses as a secretary while Schumook is the boss. Luk taunts Siu, who plays them and signals Chumook to silence Luk after the latter leaves. Luk then gets a call from Lam-luk that his wife, Donut, is in danger and asks Luk to help him but he actually tricks him to a psychiatrist's officer and suggests Luk to take therapy. A suicide bomber suddenly comes out of the elevator and Lam-luk pushes the bomber back into the elevator and sacrifices himself as he dies in the explosion. Luk breaks down as it reminded him of his wife's death, who also died in an elevator six years ago.
Ching attempts to have Fei-hung confess his crimes but the latter refuses but Fei-hung is then chased by hitmen and Ching rescues Fei-hung and flee from the hitmen. Ching then puts Fei-hung in a safety house and the brothers reconcile and Fei-hung finally confesses he was paid by Kwong to move the container full of slaves, which he was unaware of, safely to the terminal. Luk, who has been suspecting Ching, arrives with his squad outside, but the brothers manage to evade them. However, a nearby car camera captures the brothers and Luk confronts Ching back in his office but Luk persuades Ching to tell his brother turn himself in to the ICAC and promises he would not suffer a severe penalty.
Pong and Lau's squad arrive at the Hong Kong Cultural Centre where the forum will be taking place. Pong then receives a taunting call from Siu and it's revealed that Pong had accepted bribed from Siu in the past to conduct schemes. Siu then arrives at the ICAC with his lawyer to report all his crimes which he blames on Chumook. Luk's subordinate Tammy, also discovers through investigation that Pong was involved in money laundering through an offshore company and accepting bribes from Siu, so Luk rushes to the forum to protect Pong, who is the only witness that can pin Siu. Are the forum, Pong confesses her father was a corrupt judge and after his death, she continued his corrupt dealings to protect his reputation until she found out his death was caused by those who bribed him. Luk arrives and discovers Fei-hung, who was kidnapped by the terrorists, strapped to a wheelchair with a bomb and a major shootout ensues with the ICAC and police against the terrorists while EOD officers disarm the bomb. The shootout moves to the Space Museum where King appears and manages to take Lau hostage, but Pong distracts King and Luk wrestles his gun away. Noticing that King is about the detonate explosives Luk wrestles King down to buy time for everyone to leave the Space Museum before King finally detonates them where he and Luk die in the explosion.
Three months later, Siu managed to scapegoat all his crimes on Chumook, who is sentenced to fifteen years of prison. As they're walking out the court, Chumook was stabbed by the Thai slave whose sister was killed. When Siu smirks at Chumook, she takes the knife thrusted in her body and stabs Siu multiple times, killing him as she also dies from her wound. Pong was convicted obstruction of justice, but due to her many years of service to the international society, she was sentenced to three years of prison while Fei-hung was convicted of accepting bribes but sentenced to two years of prison due to cooperation in solving the sex trafficking case.
