THE EDGERTON brothers, auteurs of The Square, just might be Australia's answer to the Coen Brothers. Director Nash and writer/actor Joel have crafted a taut little gem of Aussie noir that begins, as they all do, with a simple case of indiscretion and then spirals down into a hell of unintended consequences. Very Blood Simple, illuminated by fine performances from Australian TV actors largely unknown to American audiences.

The Edgertons have given us a gritty bonbon in which no one is innocent and no good deed goes unpunished. The edge of the film lies in its ability to trick us into not knowing who is guilty of what crime. Ray (David Roberts) is a white-collar contractor cheating on his suburban wife with babe hairdresser Carla (Claire van der Boom), whose own loutish husband is a blue-collar chauvinist with criminal tendencies.

Carla finds a bag of cash that her husband has stashed away in the attic, and before the adulterers take the money and run, they arrange to have the house professionally torched to cover up their actions. Well, turns out the arsonist makes a tiny mistake. Oops, as they say in film noir circles. A is for Adultery, K is for kickback and M—well you know what M stands for.

Spare and yet fat with black humor of the funny horrible sort, The Square (the name refers to the construction site Ray manages) tightens its complex web until we're unable to breathe. Sensually perfumed with the sort of disturbing mood that Australian filmmaker Peter Weir mastered decades ago, the film thrusts us into the middle of a dingy overcast Christmas holiday, where all of the protagonists' friends meet for a picnic (Christmas falls during summer in Australia, don't forget).

The plot thickens the minute we meet Ray and Clara's spouses. As the couple's plans start crumbling, the filmmakers begin to have some fun with us as well as with their characters. To the holiday caroling strains of "sleep in heavenly peace" we stumble upon a first (or was it the second?) body. And soon the main plot of adulterers stealing stolen money transforms into a second bit of mayhem involving Ray's accepting kickbacks from a subcontractor, who is also cheating on his wife. Got that?

Half lies, partial information, mistaken glances—the tangled web takes on more twists than a bag of mutant pretzels. Suddenly Ray starts receiving crank Christmas cards asking for hush money. Only which crime is to be hushed up? The creepiness grows delicious as we, like Ray, suddenly realize that someone else knows something about the couple's plans.

Yes, but what do they know? You see how this goes. Accidents lead to more accidents, and the look on Ray's razor-edged face settles into permanent panic. In his desperation he commits a series of ill-conceived acts, while the director pours on yet more trouble in the form of recurrent nightmares and torrential rains. Everyone suspects everyone else. Cops, neighbors, workers, dogs, children and just maybe the cuckolded mates themselves. You just know this is not going to end well. Juicy, juicy, juicy.

There are no good guys in The Square and even fewer innocent bystanders. There really isn't much character development, either. Just a dark caper driven by lust, greed and botched crimes. The megatwist organizing this smart film is that we never know who suspects whom, and of what. The Edgertons let us twist in the wind for a while before unleashing a stunning climax. Worth its weight in popcorn.

THE SQUARE (R; 125 min.), directed by Nash Edgerton, written by and starring Joel Edgerton, and featuring Claire van der Boom and David Roberts, plays at the Nickelodeon.

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