Firestorm

To Shing-bong is released from prison and immediately re-joins Cao Nam's gang to hijack an armoured car transporting cash. Chief Inspector Lui Ming-chit leads his squad to arrest Cao's gang, triggering a gunfight in which Cao kills a female hostage. To suddenly rammed Lui's car, allowing Cao's gang to escape. To is arrested and claims the crash was an accident, denying any accomplice status.

To is released on bail after Yin-bing arrives with a lawyer. Lui orders his squad to tail him and keep him under surveillance. The tension between law enforcement and To grows as he tries to reintegrate. Yin-bing's intervention marks a turning point in his fate.

To promises Yin-bing that he will abandon his criminal life and start anew. She helps him find a job in a restaurant to begin rebuilding his life. The couple's fragile hope stands against ongoing police pressure and suspicion. The promise to reform becomes a fragile thread that may unravel at any moment.

The Regional Crime Unit discovers the corpse of one of Cao's underlings and the burnt remains of the getaway vehicle. Lui leads a raid on Cao's hideout after recognizing Chow in surveillance footage. A firefight erupts; Lui arrests Chow, but To and Cao manage to escape.

Police attempt to arrest Cao at his residence, but Chow destroys evidence and throws himself off a building, thwarting the operation. The setback demonstrates Cao's control and foreshadows the escalating violence to come. The pursuit intensifies as both sides double down.

Lui enlists Tong Keung, his long-time informant, to go undercover inside Cao's gang. Tong participates in the next heist, but the gang grows suspicious and attacks him. Cao's gang shoots Tong and throws his 10-year-old autistic daughter off a building; she dies from her injuries.

Lui confronts Cao near the airport after a confrontation and, following a struggle, Cao is arrested and officially charged with the murders of Tong and Yuen-yiu. The law closes in on Cao, but the path to justice remains fraught. The city reels from the mounting violence surrounding the case.

Lui receives a clip from Yin-bing's drug-addicted younger brother Kit, which reveals that Liu framed Cao by wiping the blood of Tong's daughter on him. He meets Kit, who tries to blackmail him for HK$500,000 every month. Kit dies from an asthma attack after Liu refuses him an inhaler, and Liu seizes the opportunity to remove all evidence from Kit's apartment.

Yin-bing tearfully breaks up with To, falsely claiming she is two months pregnant with another man's child. To tries to salvage the relationship by claiming to be an undercover cop. He later informs Lui that the mastermind behind the armoured car heists and the murders is Paco, Cao's sworn brother, recently released from prison. To offers to be Lui's informant on Paco under the condition that Lui tells Yin-bing about To's undercover identity.

Paco leads Cao's gang in another armoured car heist armed with heavy weaponry, which turns out to be a police trap. Special Duties Unit officers infiltrate the vehicle and a firefight erupts, spreading into the Central District. The criminals resist fiercely as law enforcement closes in.

To, having seen the video of Lui framing Cao, seizes a hostage's phone to call Lui and beg for his escape. Lui agrees but warns him not to surrender so the criminals can be killed by the police. After an intense shootout, the gang is killed and To flees the scene, only to be run over by an oncoming truck and die. Yin-bing watches the live broadcast and cries.

Lui writes a letter to Yin-bing stating that To was an undercover officer and turns himself in for his illegal actions. After giving his testimony, Lui asks the officer whether the storm is over and receives a hopeful yes as an answer, signaling a fragile closure to the case.