(CNN) -- With the exception of his character turn in last year's "Hollywoodland," Ben Affleck hasn't exactly distinguished himself with his choice of roles of late. Indeed, he's become such a media punching bag there may be a temptation to hyperbolize his first directing effort, "Gone Baby Gone," based on fellow Bostonian Dennis Lehane's novel. The truth is he's done a damn good job.
Casey Affleck plays a Boston private investigator in "Gone Baby Gone."
"Gone Baby Gone" isn't always a smooth ride, but it's a challenging, adult thriller guaranteed to foster fierce debate on the way home.
Lehane's story features the boyfriend-girlfriend private eye team of Patrick Kenzie and Angie Genarro. Their coupling isn't unique -- after all, Dashiell Hammett wrote about the married Nick and Nora Charles more than 70 years ago -- but it's still unusual enough to bring a few new angles to the well-thumbed P.I. genre.
Affleck, who also co-wrote the script with Aaron Stockard, has cast his younger brother Casey as Kenzie, with Michelle Monaghan (from "Mission: Impossible III") as Genarro. They make a nice couple, but don't get your hopes up for a "Thin Man"-like series. That's definitely not on the agenda.
This is one of those cases bigger than the sleuth who solves it. Like Lehane's "Mystic River," it involves the abuse and abduction of a child (before he became a full-time writer, Lehane worked as a counselor with abused children). Four-year-old Amanda McCready is missing, presumed snatched from her bed while her mom was visiting a friend next door.
Amanda's distraught aunt and uncle (Amy Madigan and Titus Welliver) show up at Kenzie's apartment, ignore the crap all over the floor, and hire them to join the inquiry. Angie -- she's the intuitive one, naturally -- doesn't want to get into an investigation that has an unhappy ending written all over it, and anyway, what can they hope to achieve that the cops can't?
But stubborn, determined Patrick doesn't see it that way. He's from the neighborhood -- blue-collar Dorchester -- and he knows people. He even remembers Helene (Amy Ryan), Amanda's messed-up mom; they went to the same lousy school of hard knocks. Maybe he can do some good here.
Probably the smartest thing Affleck did was surround himself with talent: cinematographer John Toll shot "The Thin Red Line" and "Braveheart"; editor William Goldenberg cut his teeth on Michael Mann's movies.
He's also capitalized on his local knowledge. Clint Eastwood and Martin Scorsese worked hard to bring Boston to life in "Mystic River" and "The Departed," respectively, but "Gone Baby Gone" feels more intimately grounded in the dirty streets and scummy bars, and the aggressive pride that comes with them. You couldn't call it a love letter to Beantown -- it's too edgy and abrasive for that -- but love-hate, maybe.
The movie tugs hard on that authenticity because Lehane's elaborate plotting works better on the page than on screen, where its cleverness inevitably feels a bit suspect. And while it's easy to sympathize with Affleck's impulse to slot Morgan Freeman into the gravitas-heavy role of a police department official, it's his only serious misjudgment. The casting puts the spotlight in the wrong place at the wrong time. Where Affleck sees only a great actor, the audience recognizes a star and wonders what he's doing there. (Fortunately, the use of Ed Harris -- playing a police detective -- doesn't detract at all.)
Casey Affleck isn't a star -- not yet, anyhow -- but he's using that to his advantage. In this movie, as in "The Assassination of Jesse James by the Coward Robert Ford," the physically slight, baby-faced actor is called upon to soak up a lot of patronizing put-downs. But he draws strength from every insult: Patrick's tougher than he looks, and when push comes to shove he's ready to prove it.
Still, he's no Bogart (or William Powell, for that matter). If he shoots somebody, he worries about it afterwards. And he keeps on worrying even after he's got the answers he was looking for. What's a dick to do if those answers don't solve anything? What if they only make things worse?
And Angie Genarro? She's the priest in this movie, on hand to offer benediction, forgiveness and ultimately penance. Whether her partner deserves better or worse is just one of the troubling question marks this superior mystery thriller dares to leave hanging in the air.
No question about Ben Affleck, though. "Gone Baby Gone" is a terrific film. This time the boy done good.
"Gone Baby Gone" is rated R and runs 115 minutes. For Entertainment Weekly's take, click here. E-mail to a friend 
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