Having an excessively cheerful day? Is an abundance of happiness irritating your friends and interfering with your work? Then why not try Undertow, the new southern drama from David Gordon Green (All the Real Girls). The first scene shows the main character impaling his foot on a rusty nail. Things go downhill after that.

Undertow tells the allegedly true story of the ill-fated Munn boys of Georgia. After the death of his wife, Dad Munn (Dermot Mulroney) is a shell of himself, rattling around in his cabin on the pig farm. First son, Chris (Jamie Bell), is surly and wayward, inclined to accidental impalements. Second son, Tim (Devon Alan), is meek and adores paint. As a beverage.

Into this social-worker-training scenario comes Uncle Deel (Josh Lucas), freshly released from the pen, full of muscles and resentment. Due to childhood differences, Uncle Deel believes that Dad has payback owing. Dad, meanwhile, shows poor attention to detail by enlisting Deel as a babysitter.

Gradually--very--Undertow takes on thriller guise. There is fighting, chasing, and harrowing escapes. But Green is much more interested in creating a sense of oppression. Everything and everyone in the movie is covered with mud, bugs, and sweat. ("Do you want to smell my armpit?" is characteristic of the dialogue.) The cars are all sagging '70s sedans, even the cop cars. Women are rare and treacherous. A dirgelike Philip Glass score carefully removes any remaining brightness and optimism. This is a compliment: the movie is a lucidly detailed freak show of hickism. As with the stories of Flannery O'Connor, Undertow depicts loser rubes, desperately poor and ruthless men who have few prospects for improvement, if by improvement you mean education and affluence (as opposed to, say, piety). It's almost a slander. Certainly, it plays on the image of the pestiferous rustic southerner. But it also seems well-researched and plausible, not to mention a tempting, if cheap, explanation for the Bush vote.