Establishing a conspiratorial tone with low-key voice-over narration, professional card player Mike McDermott (Matt Damon) ushers us into the smoky netherland of illicit poker that flourishes in musty back rooms of old buildings, protected by thick doors and beefy security guards. According to Mike, success as a rounder comes as much from reading the body language of an opponent as it does from the cards he holds.

After losing a whopping $30,000 during one bad night, Mike swears off the game and focuses on his legal studies, to the great relief of his girlfriend Jo (Gretchen Mol). The future looks bright until nine months later, when Mike's best friend Worm (Edward Norton) emerges from prison with a rakish smile on his face and a heavy gambling debt on his back. Within a short period of time, Mike is in the game again, with his relationship and studies in shambles and a major portion of Worm's debt on his own shoulders. To save their collective asses and assets, Mike must play the game like he has never played before.

Matt Damon anchors "Rounders" with another rock solid performance. He possesses something magical that goes beyond his good looks and exceptional acting skills. When you study Damon's face you can instantly picture what he looked like as a child and what he will look like as an old man. There's an air of familiarity about him that's comforting; watching him onscreen is like visiting an old friend. The film's exploration of the gritty, exotic gaming underworld is even more engrossing with Damon as our tour guide.

The chameleon-like Edward Norton creates another riveting characterization in the jittery, impulsive Worm, who comes off like a younger version of "Midnight Cowboy's" Ratso Rizzo. But, as presented in this screenplay, Worm's relationship with Mike just doesn't ring true. We're told that they have been best friends since childhood, but together they're like oil and water. Worm isn't just reckless and compulsive; he is completely self-destructive and shows no hesitation in pulling Mike down with him. Surely his behavior would have destroyed their friendship long before the men reached their mid 20's.

To be sure, the incredible loyalty Mike displays for Worm doesn't extend to his girlfriend. He appears to have little problem breaking his promises to Jo, a stable woman who stuck with him even after he blew $30 grand, choosing instead to head out for a night of rounding with Worm. The relationships between all three characters are unconvincing, playing simply as contrivances of the screenwriters to get all the cast members into their proper positions for the card games.

Pity poor Gretchen Mol, stuck with an utterly thankless role. Her job is merely to simmer, cluck at her wayward boyfriend and look wounded. Although the acting credit will be nice for her résumé, the film would have played more honestly had it omitted the role completely and just cut to the chase.

As for the other supporting characters, Martin Landau gives a luminous performance as Mike's law professor and ersatz father figure. Projecting strength, grace and warmth beneath his frail, bird-like appearance, Landau is a wonder who gets better and better with each new film. John Turturro does solid work as a man who plays not for sport, but to support his family. And John Malkovich is fun as Mike's nemesis, employing a thick Russian accent in a hammy, but engaging performance.

Ultimately, "Rounders" is a minor pleasure. The glimpse into an exotic, edgy world is absorbing and the performances of Damon, Norton and Landau are rewarding, despite the shaky credibility of their characters' relationships. But "Rounders" is frustrating because it could have been so much more, had the writers only devoted more attention to the script. Oh well, I suppose with a film like this, you just have to play the cards you're dealt.