The film functions as a "midquel," weaving together two distinct periods:
When film enthusiasts discuss the Infernal Affairs trilogy, the conversation invariably gravitates toward the first film. It is understandable; the 2002 original was a structural marvel, a cat-and-mouse thriller that redefined the Hong Kong crime genre and inspired Martin Scorsese’s The Departed . The second film, a prequel, is often praised for its Shakespearian exploration of power and loyalty. However, the final installment, Infernal Affairs III , is frequently viewed as the confusing, convoluted younger sibling—necessary for closure, perhaps, but lacking the punch of its predecessors.
The film’s central thesis is that identity is not a costume one can change at will. The tragedy of Lau Kin-ming is not that he is a bad person, but that he desperately wants to be good, yet lacks the moral constitution to achieve it. Andy Lau delivers a career-best performance here, stripping away the suave confidence of the first film to reveal a man on the verge of a nervous breakdown. Infernal Affairs III
He is not insane. He is trapped.
The final scene jumps six months later. We see Lau Kin Ming in a wheelchair, wearing a hospital gown. He has survived the shootout physically, but his mind has finally collapsed. He suffered a bullet fragment lodged in his brain, leaving him in a persistent dissociative state. The film functions as a "midquel," weaving together
Yeung represents the mirror image of Lau. While Lau is a criminal masquerading as a cop, Yeung appears to be a cop who might be a criminal. This ambiguity drives Lau to madness. In the 2004 timeline, Lau is convinced Yeung is another mole, projecting his own guilt onto a rival. The dynamic between Andy Lau and Leon Lai is electric, characterized by a cold war of stares and subtle accusations.
(Tony Leung), detailing his undercover operations, his relationship with psychiatrist Dr. Lee Sum-yee However, the final installment, Infernal Affairs III ,
Picking up almost immediately after the shattering ending of the first film, we follow Inspector Lau Kin-ming (Andy Lau). Haunted by guilt and paranoia, he is now lauded as a hero for dismantling the triads, but he is living a lie. The story interweaves two timelines: the present day (roughly 2003) where Lau tries to bury his past as a mole, and a flashback to 1991, showing the uneasy partnership between Lau and the late gang boss Sam (Eric Tsang), as well as his first, chilling encounters with the unstable Superintendent Yeung (Leon Lai).
Leon Lai as Yeung Kam-wing and Chen Daoming as Shen Cheng are praised for adding fresh, ambiguous energy to the series.
While the first film asks, "What if a cop lives as a gangster?" and the second asks, "What if a gangster is born?" , the third asks the most terrifying question: