TL;DR

It's over two decades old, but Infernal Affairs remains THE gangster trilogy.

*SPOILERS AHEAD* *SPOILERS AHEAD* *SPOILERS AHEAD*

The Hong Kong Police and a triad have placed moles in each other's ranks. Tony Leung is Chan Wing Yan, an undercover cop desperate to leave his assignment.

The antagonist is Senior Inspector Lau Kin Ming (Andy Lau), a decorated policeman who is actually a mole for Hon Sam (Eric Tsang), a triad boss.

It's a game of cat-and-mouse, with policemen and gangsters trying to uncover the moles before their opponents do.

Setting the stage

Infernal Affairs is a trilogy. To me, it requires three movies to finish telling the story.

Infernal Affairs is the main story, but it needs Infernal Affairs 2 for context. It explains the characters' history and the events that shaped them.

Others complain that Infernal Affairs 3 is "bad". It is not. It brings closure to the tale. Without it, the villain never gets his comeuppance. In this context, Infernal Affairs 3 is neither short on emotionality nor poignant moments.

I have watched the trilogy at least five times, and after each viewing, I still learn something new. There are nuances and subtleties that can only be gleaned with each viewing. That is a hallmark of a well-told story.

It's too much to cover all three movies in one post, so instead, I'm highlighting seven moments from the first film that I found unforgettable.

1) An unending assignment

Wing Yan is ordered to undergo psychiatry sessions to deal with his anger-management issues or face jail time. Exasperated, he yells at SP Wong (Anthony Wong), reminding him that this assignment was originally three years, but it's been almost 10.

Wing Yan lives a double life: As a gangster, the police chase him. As a mole, gangsters are after him. It's unending psychological and emotional torture.

Sam smashes open Wing Yan's cast

2) Tap... tap-tap... tap-tap-tap...

During operations, Wing Yan and SP Wong communicate using morse code to avoid bugs and circumvent the fact that they can't call or text each other.

As the deal between Sam and the Thai traffickers goes down, SP Wong stands with his eyes closed. At the triad hideout, Wing Yan stares pensively out the window. Our eyes are drawn to the cast on his arm.

At the scene's climax, the police ambush Keung (Chapman To), one of Sam's henchmen, as he carries bags of cocaine ashore. Sam yells at him over the phone to dump them. The deal falls through. Sam glares at his men, his seething gaze an attempt to uncover the traitor.

As Wing Yan begins to speak, Sam grabs his injured arm and smashes it on a table to shatter the cast, suspecting that it contains a bug. It's empty; Wing Yan's cover is intact.

Later, we see the mic taped outside the grubby window he'd been staring out of. Nobody suspected his finger-tapping to be morse code.

Kin Ming executes his boss

3) Betraying his boss

One of the most brutal scenes in Infernal Affairs is when Kin Ming betrays Sam. The police ambush Sam in a multi-storey carpark and Sam flees on foot, desperation on his face.

Sam calls Kin Ming. The sound of a ringing handphone pierces the silence, echoing off the concrete walls. Kin Ming appears and shoots Sam dead, revealing him as a two-faced, cold-blooded and remorseless killer who stops at nothing to get what he wants. Sam was a criminal, but he was also a father figure. But Kin Ming executed him without a second thought.

4) Keung was undercover, too

Keung was shot and mortally wounded during the gun battle between the cops and the triads. He and Wing Yan flee. Behind the wheel, Keung grows visibly weaker. He loses control and crashes the car. Dying, he tells Wing Yan that Sam said, "Whoever didn't show up today was the mole. I didn't tell him you went for a massage."

Keung was a loud and sometimes naive character. But the surprise is that he was a police mole, as confirmed by the news report in a subsequent scene.

Mary makes a painful allusion to Kin Ming

5) Mary learns the truth

Mary (Sammi Cheng) is Kin Ming's fiancé and a writer. Kin Ming comes home and sees Mary sitting on the steps, visibly upset. The sampler CD plays Forgotten Time by Tsai Chin. Suddenly, a recording of a conversation between Sam and King Ming plays.

Mary says she can't finish her novel because she can't decide whether the main character is good or bad. Tearfully alluding to her fiancé, she says, "I think only he knows."

6) SP Wong dies

Wing Yan's expression is priceless. In that moment, his whole world came crashing down – SP Wong is the last and only person in the department who knows Wing Yan's true identity as an undercover cop. It is a look of despondent horror. For the first time, his character knows not what to do.

The iconic rooftop scene between the villain and the hero

7) Wing Yan dies

Wing Yan arrested and handcuffed Kin Ming following their rooftop meeting, but suddenly, another policeman confronts them, gun drawn.

Using Kin Ming as a shield, Wing Yan backs into the lift. But as he turns his head, he provides a small opening to the cop, who shoots him. It turns out the other cop is also a triad mole.

The lift descends as gunshots ring out. The doors open to a bloody scene: The other mole also lies dead; Kin Ming shows his warrant card to the waiting policemen.

There are many other moments in Infernal Affairs that are equally memorable, from the revelation that Wing Yan has a daughter to confessing to the psychiatrist that he's actually a policeman (it was painfully obvious he was serious but he pretended it was a joke) to Wing Yan's funeral.

But these seven struck me the most and are ultimately the ones that made me eager to watch the next instalment.