(Hong Kong) Director Dante Lam’s 2008 film “The Beast Stalker” serves as a foundation for “The Stool Pigeon.” In the earlier film he uses the same cast to describe the conflict of morality between a cop and a criminal, with Nick Cheung’s hitman character being pursued by a police detective (Nicholas Tse) around the Fringe Club. The two play cat and mouse in the dark, narrow corridors inside the pre-war colonial building, making it one of the most interesting scenes in that film.

But this year’s “Stool” sees Lam in his best form yet. He fully embraces Hong Kong locations and architecture as his playground using the uniquely intricate alleys in street markets and a squatter village, and even piled-up school desks and chairs in an abandoned classroom. The film also has some of the most exciting action scenes ever, which makes “Stool” an almost impeccable film.

Cheung’s portrayal of a hitman in “Beast” won him Best Actor at the Hong Kong Film Awards, but this time his and Tse’s roles have been reversed. Cheung plays a police inspector called Lee who specializes in using snitches (stool pigeons) to collect evidence to arrest criminals. When he hears that Barbarian, Hong Kong’s most wanted criminal, has returned to rob a jewelry shop, he knows he’ll need an informant. He discovers that Barbarian has a getaway driver called Ghost (Tse), a car thief fresh out of prison, and sets out to persuade him to become his snitch.

According to Lee, the snitch system is all about free will—one has the choice whether to give information and receive in return a very generous payment—but this is just Lee’s salesman pitch. Once you’re in the system, there is no way out and Lee is still haunted by the misfortune of his last snitch Jabber (Liu Kai-chi). But in Ghost’s case, he has no option. He can choose not to snitch, but how else is he going to repay his million-dollar debt?

What happens next is, in a cinematic sense, a very tight, expertly made piece of work. As said, Lam has turned Hong Kong into his playground to stage exciting scenes. Who needs to spend $10 million building Hong Kong on a soundstage, or shooting a Hong Kong film in another city? Lam has understood that the streets and passageways we think are mundane are actually perfect filming locations—something directors like Wong Kar-wai knew 20 years ago.

On top of that, Lam has developed three-dimensional characters that make your heart sink when you watch them suffer through bad choices. Cheung has stepped up after his last award-winning performance with more subtlety and style; while Tse has turned into a very effective actor who stays in the background instead of outshining people just because he’s an idol. Every step along the way, these characters are in pain and you can empathize with them. Once in a while the most excellent film comes with a heartbreaking feeling that haunts you even after you walk out of the cinema. And “Stool Pigeon” is one of those films.