To call Blue Ruin a revenge thriller is to sell this barbed-wire-sharp and altogether surprising American indie short.

Yes, the main character, Dwight (Macon Blair), is driven - in the rusted Pontiac Bonneville that gives the film its name - to exact vengeance on his parents' killer. Along the way, though, writer/director Jeremy Saulnier finds time to explore a substratal world of homelessness, of a solitary soul scrounging for food and shelter. And the film's spare, unstinting look at how violence defines our lives is as jolting as it is true.

Blue Ruin begins innocently enough, with the bearded, scruffy Dwight enjoying a bath in a clean, well-appointed house. Then he hears a car pull up, and he bolts out of the tub, out the bathroom window, on the run. Only then do we realize he had broken into the house.

From a police officer who had taken kindly to this wary-eyed beach bum who lives in his car parked behind the dunes, Dwight finds out the man sent to prison for the murder of his mother and father is about to be released in a plea deal. He steels himself for the trip to the prison - stealing supplies and weapons as he makes his way.

Blair's Dwight is not your typical Hollywood avenger: He's slack, bumbling, unprepared. He'll smash a car window only to realize what he's taken won't work or can't be put to use. When he finally confronts the man who has done time for killing Blair's kin, the whole thing is a bloody mess, literally.

The aftermath of this encounter - in the men's room of a roadside bar - devolves into a nightmare of mistakes and misjudgments. Dwight belatedly realizes his estranged sister and her children have been put in jeopardy by what he has done. Somehow, he has to make things right.

Blair and Saulnier are childhood friends and canny connoisseurs of payback thrillers and B-movie gore. Casting someone as apparently unheroic and unremarkable as Blair in the role of a justice-seeking warrior was a brave and, ultimately, brilliant choice. Dwight is the hapless Everyman forced to find the resources - and courage - to do what he must. But he might not have either.

Blue Ruin feels of a piece with other recent films (Joe and Mud come to mind) that survey the landscape of rural America and find drunks and thugs, spooked kids, and drifters hiding in the weeds. But the lack of any readily identifiable star - no Cage, no McConaughey - makes Blue Ruin feel even more authentic, more rooted in this frightening world.

Blue Ruin ***1/2 (Out of four stars)

Directed by Jeremy Saulnier. With Macon Blair, Devin Ratray, Amy Hargreaves. Distributed by Radius-TWC.

Running time: 1 hour, 52 mins.

Parent's guide: R (violence, profanity, adult themes).

Playing at: PFS at the Roxy.EndText

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