When a film adapted from a novel is better than the book, either the film is exceptional, or the novel wasn't all that good to begin with.

Both scenarios certainly apply to "A Simple Plan."

A chilling examination of greed (both in terms of subject matter and the snowy Midwest setting), "A Simple Plan" is certainly the most intense thriller to come along in many a moon, and perhaps the most thought-provoking as well.

The fact that the film is deliberately paced and that its violence is somewhat restrained has to be considered a surprise — especially since it comes from director Sam Raimi whose movies aren't exactly noted for subtlety. (His filmography includes the "Evil Dead" films, "Darkman" and "The Quick and the Dead.")

Also, first-time screenwriter Scott Smith (who also wrote the best-selling novel) has made some wholesale changes to the story, such as placing more concentration on different characters. And they are changes that work.

Of course, it doesn't hurt that he's writing for an excellent cast, led by Bill Paxton and Billy Bob Thornton, playing brothers whose lives are changed by fortune — in the form of $4 million in cash they find in a downed plane.

Initially, Hank Mitchell (Paxton) wants to report the loot to the authorities, but his unemployed and underachieving older brother Jacob (Thornton) wants to keep it. So Hank agrees to hang on to the cash until they can find out whether anyone is looking for it.

But the situation quickly spirals out of control. First, Jacob apparently kills a farmer who stumbles on them as they are covering their tracks. Then, another "partner" in the arrangement, Jacob's buddy Lou (Brent Briscoe), tries to blackmail Hank into giving him a "loan."

In desperation, Hank reveals his secrets to his pregnant wife, Sarah (Bridget Fonda), who at first begs Hank to turn the cash in. But once she sees how much money is involved, Sarah becomes a willing accomplice, and the two discover exactly how far they'll go to protect the fortune.

Though some of the situations may seem a bit contrived, Raimi pulls them off nicely, thanks to his low-key approach. In his capable hands, the tension becomes almost unbearable, and the character interactions seem genuine.

Paxton's agonized expressions perfectly mirror his character's inner turmoil, while Fonda's transformation from a horrified bystander to a malicious schemer is even more believable.

Both, however, pale in comparison to Thornton, who is heartbreaking as a slow but sweet-natured loser who can't see the game of shifting alliances that's going on around him.

"A Simple Plan" is rated R for violent gunplay, profanity, gore and some gruesome makeup effects, use of vulgar slang and brief female nudity.