Purple Storm

Soong orchestrates a plan to smuggle the chemical weapon Ricin-X to Hong Kong by sending his son Todd Nguyen and Guan Ai on a North Korean freighter bound for Hong Kong. A Korean assassination team boards the ship to retrieve the container, but they are killed, and Todd is knocked unconscious. Guan dumps the container overboard and the duo flee, leaving the mission in disarray.

Todd receives medical treatment in Hong Kong and is revealed to be a wanted criminal. He is suffering amnesia, triggering police interest and a plan to recover him. Ma Li and the Anti-Terrorist Force bring in psychologist Shirley Kwan to help restore his memory.

Kwan suggests implanting a new identity for Todd so he can operate undercover for the police. Ma initially objects on moral grounds, worried about turning a man into a tool. The debate sets up the moral conflict at the heart of the operation.

During investigation, Soong's Cambodian associate dies by an apparent suicide at the scene, but Ma spots Soong among the observers before he disappears. The encounter confirms Soong's operative presence in Hong Kong. The case escalates as the chase for Soong tightens.

Soong breaks into a local TV station, using old broadcasts to identify Ma and manipulate the narrative. He plants a bomb, which is detonated the next day by an employee, and CCTV confirms his involvement. The attack raises the stakes and tests the police's readiness.

Fearing a hospital rescue, Ma orders Todd back to ATF HQ and stages an ambush. Soong's team disrupts communications, kills the ATF squad, and escapes, but Todd is not captured. Ma's plan to leverage the undercover option moves forward.

Ma agrees to Kwan's undercover plan, but Todd experiences disorienting flashbacks of his true past, complicating the mission. The conflict between memory and role adds tension to the operation. The team recalibrates its approach as events spiral.

Soong meets Todd on the pedestrian bridge in Wan Chai North under the promise of a meeting. An ambush of snipers and undercover officers erupts amid an explosion from a nearby building. Guan appears, stabs Todd's neck with a syringe, and escapes with the unconscious Todd on a passing vehicle.

Soong tries to 'cure' Todd by involving him in familiar activities and moving toward a vessel-based operation. Guan secretly hires a ship to recover the chemicals, while Ma plans an ambush at the shipyard and keeps Todd's undercover role from the rest of the force. The ensuing fight leaves many casualties and Todd is forced to confront his loyalties.

A police convoy is blocked by a bomb-triggered trap as a bomb detonates in the attacker’s lap. Guan triggers another explosive in front of Todd, triggering flashbacks about his son's death. Ma orders a city-wide sweep for more bombs.

At Kai Tak Airport, Guan and Todd slip into restricted areas and are confronted by Airport Security Unit officers, whom Guan shoots in a shocking moment. Soong recovers the chemicals and Ma realizes the plan is to hijack a plane to seed clouds; the SDU races to the airport while most are diverted to Chek Lap Kok. The tension mounts as authorities scramble to respond.

Guan and Todd infiltrate the hangar, kill technicians, and hijack a small plane. Soong arrives with the chemicals, but a gun battle erupts and Guan is fatally injured, sacrificing herself so Todd can escape with the chemical cargo. Soong presses forward with his plan.

Ma and the SDU reach the tunnel where Todd and Soong are cornered. They trap the pair at both ends and engage in a brutal struggle. Soong is severely injured by Ma, but activates the chemical bomb and dies; Ma pulls Todd out as the tunnel gates slam shut to contain the blast.

In the aftermath, Todd disappears into the night and leaves Hong Kong under the protection of Ma, with the truth of his memory and loyalty left unresolved by others. The final shot hints at a fragile peace as he heads toward the new Hong Kong International Airport.