Only five years after the horrific events of 9/11, there have been several motion pictures that have dealt directly with the subject, from 2006's staggering "United 93" to Oliver Stone's maudlin "World Trade Center." "Reign Over Me," written and directed by Mike Binder (2005's "The Upside of Anger"), views the tragedy from a different perspective—that of a man unable to cope after he loses his entire family in one of the plane crashes. It's a weighty topic, and could have gone wrong in two ways: with too heavy a hand, it might have been sappy, and treated as a purely dark exploration, it could have become morbidly oppressive. If the finished product is far from faultless, credit Binder for tackling such a premise with a heartfelt toughness that celebrates the simple joys in life even as it doesn't shy away from the unthinkable sense of loss at its center.

Set entirely in the present day (or close to it), Alan Johnson (Don Cheadle) is a New York City-based dentist and family man who, when he isn't rebuffing the hungry sexual advances of a kooky patient named Donna (Saffron Burrows), feels as if his life is stuck in a rut. He has a wife, Janeane (Jada Pinkett Smith), and two daughters at home, but he isn't particularly content with his chosen profession and the spark in his marriage has started to dim. When Alan spots old college roommate Charlie Fineman (Adam Sandler) driving through the city on his motor scooter one night, the two of them quickly rekindle their friendship.

It is blindingly clear, however, that Charlie isn't all right. Spending his hours recoiling from the world and avoiding virtually all human contact through playing video games, listening to music on his headphones, and obsessively remodeling the kitchen in his apartment, Charlie refuses to even acknowledge that, only a few years before, he led a happy domestic existence with a wife and three children. At the expense of alienating himself from his own family, Alan is determined to break through the painful walls Charlie has built up and help him take the first steps in moving on with his life.

More of a low-key character drama than a marketable plot-driven effort, "Reign Over Me" does a confident job of showing the realities of a person paralyzed by grief and unsure of how to handle it. This isn't some fantasy sitcom world where things are easily solved in a couple hours, but a close approximation of what many people must go through when faced with tragedy. The newfound bond between Alan and Charlie comes at a time in both their lives when they desperately need it. For Alan, Charlie is the bridgeway to an idealistic past, when he believed anything was possible and his whole future was still undetermined. For Charlie, Alan's friendship is the very first human connection he has allowed in years. Together, they form a sort of dysfunctional, two-person makeshift support group, but this, too, doesn't come easy; Charlie has been forever changed by the deaths of his loved ones, and has a long, arduous road ahead of him if he is to rejoin the world of the living.

Don Cheadle (2004's "Hotel Rwanda") is his usual impressive self as Alan Johnson, at the top of his game in the tartly written scenes set at his workplace and in the more somber segments at home as he navigates the lack of communication between himself and Janeane. When put up against Charlie, though, Cheadle's Alan takes the role of nurturer and is the less interesting of the two protagonists. As Janeane, Jada Pinkett Smith (2004's "Collateral") plays all of her scenes in the interior space of their apartment. Smith is effective as a woman who senses the distance between herself and Charlie, but deserves better than being relegated to emptying the dishwasher and folding towels. Lending support with the minimal material left for them, Liv Tyler (2004's "Jersey Girl") projects warmth and a kind nature as Angela, a young therapist Charlie goes to, and the sorely underworked Melinda Dillon (1999's "Magnolia") is excellent as Ginger Timpleman, Charlie's estranged stepmother.

As for the difficult part of Charlie, a powerhouse performance is required to bring out the whirlwind, combative emotions of this broken human being, and Adam Sandler (2006's "Click") is regrettably not the person to give it. This is the most dramatic and demanding turn of Sandler's career, no doubt about it, but his acting is uneven as he turns Charlie into someone who seems to not only be suffering from grief, but also a mental disability. Sandler is fine most of the time, and is remarkably touching in the critical centerpiece sequence where he finally decides to express his feelings about his family. There are other times, however, when his personal speech patterns—eternally more suited for playing comedy—get the best of him, turning sincere moments into examples of over-the-top, unintentionally humorous histrionics.

"Reign Over Me" is affecting in its own right, and the soundtrack, featuring classic cuts from Bruce Springsteen, The Who and The Pretenders, compliments the onscreen action and the emotional place that the characters are in. At the same time, one can't help but wonder how much better the film could have been with someone other than Adam Sandler in the role of Charlie. A tighter, more assured grasp on who this man is and how he should be played could have smoothed out the rougher edges. Likewise, an early scene or flashback to him before his family's untimely deaths might have given the viewer a clearer picture of the enormity with which he has been altered. This casting glitch and a few narrative hiccups besides, "Reign Over Me" gets enough right that it deserves to be seen. The ending, like much of what comes before it, remains honest and true, signifying hope for Charlie and Alan without having to spell it out.