The artwork of Infernal Affairs recalls Running Out Of Time and cinema-goers, when the film opened in Hongkong last December, must have been expecting a witty thriller in the Johnny To mode. What they got instead was a dark, gritty urban thriller.

In Infernal Affairs, Eric Tsang is triad chief Sam who believes that every plan must have a back-up, and every back-up an alternative. Early in his criminal career, he has his people joining the police force (who would later be his informants) - among them Ming (the younger Ming is played by Edison Chen while the older Ming is portrayed by Andy Lau). On the other side of the fence is Inspector Wong (Anthony Wong), who gets Yan (Shawn Yu) "thrown out" of the force. Yan (Tony Leung Chiu-Wai) then joins the triad and ends up a trusted member of Sam's outfit.

When the film starts, both Yan and Ming, who have been so immersed in their double-crossing lives, are beginning to question themselves: "Who am I?" The problem is even severe enough for Yan to see a psychiatrist (Kelly Chan). Ironically, Ming is involved with a writer (Sammi Cheng) working on a book about doppelgangers. The film tries to resolve the internal conflicts that plague these two, but why the ambitious Ming wants out isn't so clearly put across.

A film about two characters leading double lives is rich with drama and Infernal Affairs does not fail in this department. In the film's running commentary (in Cantonese), the cast and crew point out that everyone understands and tries to showcase the anguish that the two leads feel. Strangely then the tension in the film does not derive from this angst but from the efforts each side makes to undercover the mole in their midst. The two instances where the weight of his actions seem to be unbearable is when Yan witnesses the death of his mentor and when Yan's buddy dies trying to save him.

The joy of watching Infernal Affairs is not so much the tight ensemble acting among some of the top Hongkong actors today, but that they are all in this movie together, and not fooling around! Tony Leung fans might remember him in a similar role in Hard Boiled so playing an undercover cop is nothing new, but he did snag the Best Actor Award at this year's Hong Kong Film Awards. The standout actor is actually Eric Tsang. With his cherubic face, Tsang comes across as a non-threatening businessman but wait till you see that sinister glint in his eyes.

The box-office and critical success of the film must have surprised the filmmakers though on hindsight, Infernal Affairs does stand out from the usual run of cheesy ghost and love stories. (The other notable exception in 2002 is Golden Chicken, directed by Samson Chiu and stars Sandra Ng as a hooker with a heart of gold. The film also stars Eric Tsang and Andy Lau, the latter practically plays himself - cheeky pun intended). Infernal Affairs has spawned two follow-ups - a prequel and a sequel. While the sequel neatly wraps up the story, it is the murky web of intrigue and shady charactersations (aided by superb photography, Christopher Doyle was a consultant) that make Infernal Affairs a much more involving journey into Hell than the straight-forward story found in its heart. (7) - Stephen Tan