Infernal Affairs

Chan Wing-Yan, a dedicated police officer, begins his mission to infiltrate the organized crime triad. His commitment to this dangerous assignment places him deep within the criminal underworld of Hong Kong, where he must constantly navigate challenges and maintain his cover.

Lau Kin-Ming secretly works within the Hong Kong Police Force while serving the gang leader, Hon Sam. His role in the police department allows him to provide crucial information to the triad, complicating the dynamics of trust among law enforcement and criminals.

Amidst his undercover work, Chan communicates vital information to his superior, Superintendent Wong, using Morse code. This hidden method enables him to alert Wong about an impending drug deal between Sam and the Thais, showcasing the lengths he goes to maintain his mission.

As the drug deal is set to take place in an apartment with the transfer at sea, Lau sabotages Chan's mission. By sending a warning SMS to local cell phones, he ensures that Sam destroys all evidence, revealing the treachery existing within both camps.

In the aftermath of the botched drug deal, both Wong and Sam ramp up their investigations to find the informants in their ranks. The atmosphere grows tense as suspicion mounts, particularly between Chan and Lau, who are unaware of the other's true allegiance.

Chan tracks down Sam in an effort to gather crucial intelligence regarding the triad's activities. However, during a tense exchange in a dimly lit theater, he becomes distracted by a phone call, allowing Lau to slip through his fingers and escape.

Wong plans to extract Chan from his undercover role for his safety but remains unaware of Lau's watchful eye. This ignorance leads to Wong's horrific fate as he is caught by Sam's henchmen and thrown from a building after refusing to reveal Chan's position.

Grabbing Wong's phone, Lau reaches out to Chan with a plan to thwart Sam's drug deal. Though the operation yields significant arrests, Lau's intentions remain self-serving, hinting at his ultimate betrayal.

On the rooftop where Wong met his end, Chan and Lau face off in a tense showdown. Chan disarms Lau and raises his weapon, placing him at the mercy of Lau's desperate plea for redemption against the backdrop of their bitter rivalry.

As the tension escalates, Inspector B arrives and demands Chan put down his weapon. In a shocking twist, Chan is shot by B, who reveals himself as another mole working for Hon, further deepening the web of deception.

Immediately after Chan's shocking demise, Lau murders Inspector B, eager to eradicate any loose ends from his past. This act of brutality illustrates Lau’s complete transformation from mole to a seemingly legitimate officer in the eyes of the force.

Upon reaching the ground floor, Lau boldly reveals his identity as a mole to fellow officers. This declaration solidifies his fate as he takes the necessary steps to align himself completely within the police structure, while the ramifications of his actions begin to unfold.

In the months following Chan's death, his psychiatrist, Lee, uncovers the truth of his undercover status while grieving his absence. This realization ignites a sense of loss about the costly sacrifices made by individuals on both sides of the law.

Lau attends the funeral of Chan, reflecting on the choices he made that led to such tragic outcomes. These moments of introspection force him to confront the duality of his existence, haunted by the legacy of betrayal he has left behind.

An alternative ending produced for audiences in China and Malaysia showcases Lau's identity being unmasked, resulting in his arrest. This variation adds complexity to the narrative and suggests potential consequences that linger even after the story concludes.