Minnesota is very snowy indeed when brothers Hank (Bill Paxton) and Jacob (the astonishing Billy Bob Thornton, with yellow buck teeth and clunky spectacles) make a life-changing discovery. It’s a crashed plane that they inadvertently uncover in the nearby woods, en route home from paying annual respect at their parents’ grave. Together with Jacob’s rotund, obnoxious friend Lou (Brent Briscoe), they dig out a duffel bag containing $4.4 million in 100-dollar bills, and leave the dead pilot to the crows pecking his eyes out. Yes, in case you were in any doubt, we’re in Hitchcock territory.

Hank’s instinctive reaction is to inform the police, but Lou, greedy-eyed, and Jacob, mouth agape, call a time-out. Who would ever know if they just took the money and never came back? Hank agonises for long moments, and eventually agrees to keep the money on the sole condition that he hold on to the whole lot until the snow thaws and the coast becomes manifestly clear.

So begins Scott Smith’s tale of shaky loyalty, deadly, niggling insecurity and distrust, patterned along the lines of The Treasure Of The Sierra Madre (1948), The Naked Spur (1953), or, if only superficially, Shallow Grave (1994). As things begin to fall apart, anxiety necessitating a return to the scene and unexpected bloodshed, the bond between the two brothers is sorely tested by the interfering machinations of Lou and a spiralling sense of guilt. Hank’s pregnant wife Sarah (Bridget Fonda) becomes instrumental in directing his fears towards Lou, and ensuring that Jacob, a helplessly lonely sad case, comes down on his side.

Despite Fonda’s perfectly decent supporting turn, Smith’s screenplay from his own tautly compelling novel is really all about the brothers. Paxton’s Hank is the more balanced and normal of the two, a happily married man with basic if highly pregnable moral scruples and a protective attitude towards the freakish, unassertive and pitiable Jacob. Thornton invests this role with heartbreaking humanity and pathos – no actorly fireworks, but a compassionate and perfectly communicated understanding of awkwardness, failure and despair in excelsis. His laboured speech and agonising attempts at humour are more painful to watch than any of the physical violence here.

Raimi also directs him brilliantly, leaving him in door-frames or isolated in tight close-ups, trying pathetically to stamp some kind of presence on to scenes and dialogues. For a while you think that Thornton is doing what only the most intelligent actors are capable of – playing stupid realistically. After the credits rolled, comparisons that sprung to mind were Dustin Hoffman’s Raymond Babbit in Rain Man (1988) and John Malkovich as Lenny in Of Mice And Men (1992). But an important realisation comes in the final stages of the film, which is that Thornton’s Jacob has a more intuitive understanding of what’s really going on that anyone else.

Where Hank buries his bleeding conscience under layers of practicality, helped by the bleak picture Sarah paints of their former life in one key speech, Jacob lays everything bare. His soul-searching is not made less profound by the fact that it lacks any kind of vocabulary. Jacob’s automatic recourse to terms as monochromatic as good and evil actually existentialises the brothers’ dilemma and provides the important core of the film’s moral philosophy.

There’s a lot going on in Paxton’s portrayal too – unusually for this often nondescript actor. The finesse of both novel and film is to get us to sympathise with the man who must become the most cold-blooded of all the accomplices, not primarily through an excess of greed, but for self-preservation’s sake. His repeated threat to burn the money if the slightest hint of their involvement is betrayed isn’t just a bluff; without Fonda’s gradually worsening influence we suspect that paranoia might drive him to exactly that in order to wipe the slate clean. But it’s the combined love and shame he feels for Jacob which drives him to the most desperate acts to keep them both safe. Like Michael Douglas’ entire career, Paxton’s role here is that of Everyman under siege from the whole range of devices and desires, submitting to temptation like the prototypical Everyman in the garden of Eden. And as with Douglas’ D-Fens in the final moments of Falling Down (1992), we witness Paxton’s incredulity as he realises that he has, in movie terminology, become the bad guy.

This isn’t the kind of film-making you expect from the director of the Evil Dead trilogy. Raimi goes so far in the direction of sensitivity and restraint with this film that there are moments when you’d quite like him to indulge himself with an insanely accelerating zoom shot at ground level. But you’d be wrong. A Simple Plan also shares a similar locale and generic content to Fargo (Raimi being a long-time collaborator and friend of the Coen brothers) – and perhaps you’d like this to be similarly shot through with self-ironising black humour. But you’d also be wrong.

Remember, Raimi made Darkman (1990), which, though stylised in an almost antithetical way, generated a similar pathos for its freakish involuntary protagonist. And here – as in Dead Ringers (1988), perhaps, or American History X, another powerfully acted drama about brothers made in the same year – he delivers a displaced tragedy about two personalities that are really one, and pulls it off with a fantastic economical power, sober content deserving and getting a perfect stylistic fit.

Tim Robey