David Cronenberg is out of his element in "A History of Violence," and it shows.

The director best known for an edgy, uncanny, sometimes gruesome style of cerebral macabre tries to put his stamp on this graphic novel adaptation about the humble owner of a small-town diner (Viggo Mortensen) thrust into a dark world of mobsters and a confrontation with his own identity. But the film feels fresh and vital only in the darkly humorous opening scene, involving two cold-blooded thugs checking out of a motel, and during the second act in which Mortensen's family comes under threat after he spontaneously shoots the very same thugs (with their own guns) when they attempt to violently take over his restaurant.

As a result of his heroism -- and the suspicious precision of his kill -- members of the Philadelphia mafia who saw Tom Stahl (Mortensen) on TV soon come to town convinced he's one of them -- the runaway brother of a crime boss who left a lot of gangland untidiness in his wake when he disappeared some 20-odd years before.

For a good 40 minutes in the middle, "A History of Violence" is a concerto of elements that keep you off-balance with recurring danger and bursts of startling violence that have unexpected origins, unforeseen results and far-reaching consequences for Tom, his family and his long-blissful marriage. Cronenberg can make even a bucolic shopping mall feel ominous to Tom's wife (Maria Bello) -- even as it remains entirely benign to everyone around her.

In this section of the film, the director also expands upon how Tom's courage and celebrity has a trickle-down effect on his family -- especially his picked-on teenage son (Ashton Holmes). The shifting family dynamic and a potentially dangerous shift in Tom's psyche provide the film with layers of tension and emotion that Cronenberg plays perfectly.

But up until the shooting that changes their lives, Cronenberg tries so hard to make the Stahls seem mundane and average that the film could almost put you to sleep. Save one awkwardly candid marital sex scene, there's nothing remotely interesting about these people. Then later, once the plot moves beyond questions about Tom's history and toward a confrontational climax, "A History of Violence" becomes as rote as a Hollywood revenge thriller.

Certain characters provide terrific splashes of color -- a seething and disfigured mob enforcer played by Ed Harris, a kingpin underplayed with dark humor and intimidating calm by William Hurt, cast brilliantly against type. But the longer the movie goes on, the more it looks like a Mel Gibson-style family-man-as-action-hero flick made on the cheap, albeit with a little more depth thanks to Cronenberg's direction and Mortensen's elusive and involving performance. The finale even lacks real-world consequences, just like a Hollywood shoot-'em-up.

So when the credits roll, you might be left wondering, Why was this routine (if slightly unpredictable) multiplex movie made as a low-budget independent? And just what drew such talented, independent filmmakers and actors to its shrug-worthy script?