When a computer disk belonging to recently resigned and embittered CIA agent Osborne Cox (John Malkovich) is found in the ladies toilet at a Hardbodies gym in Washington, co-workers Linda (Frances McDormand) and Chad (Brad Pitt) believe they have a rare chance to make big money selling it back to him. As Linda and the hapless airhead Chad try to flog off the disc to anyone who'll buy it, they stumble about causing endless trouble for everyone, not least themselves.

Coen heat cools with D.C. crime comedy.

With their new screwball comedy Burn After Reading, the Coen Brothers invent another way to explore the notion of ignorance and consequence.

A poor sap sees an easy route to life fulfilment and leaps in without any inkling of the repercussions. They've played this premise for laughs with Raising Arizona, centring on barren newlyweds, a kidnapped quintuplet and an apocalyptic bounty hunter. They've ramped up the tragedy with No Country for Old Men, with their cautionary tale of a sticky-fingered everyman, a cash-filled suitcase and er, another apocalyptic bounty hunter. And they've landed somewhere between the two extremes with Fargo’s tale of an embezzling used car salesman pursued by a slow-moving but quick-witted state trooper. Clearly, the boys are big on consequences.

This time around, the poor saps in question are gym workers Chad Feldheimer and Linda Litzke (Brad Pitt and Frances McDormand) and the McGuffin of choice is a computer disc thought to contain top secret CIA files. Unlucky-in-love Linda is desperate to fund an extreme makeover to improve her chances with the gents, and Chad offers that the disc’s rightful owner might like to contribute to her expenses.

Suffice it to say, as blackmailers, Chad and Linda make good personal trainers.

As we've come to expect, a Coen plot is just a meandering means to an end, populated by loveable lugs, cold-hearted SOBs and a wide-variety of oddballs. And so it is with Burn after Reading. Chad and Linda’s flawed plot coils in on itself and ensnares a disgraced former agent Osborne Cox (John Malkovich), his unsympathetic and unfaithful wife (Tilda Swinton), her doofus lover (George Clooney) and The Russians.

Which makes Burn after Reading sound a whole lot funnier than it actually is. This is not one of the brothers’ best, it must be said, for though it has some funny moments, it never quite amounts to anything more than the sum of its parts.

A high-pedigree cast resorts to the kind of mugging best left to a Christmas panto, and Pitt is all wide eyes and goofy grins beneath a shock of frosted hair. His profession makes him an entirely different kind of Joe Six-pack but one whose ignorance of the high stakes world of D.C. rivals only that of you-know-who. Mind you, those in the intelligence community are no wiser than Chad. Malkovich’s Cox may bluff and bluster like an old-world operative but you soon get the inkling that he’s just a clueless and embittered ol’ boozehound. Similarly, CIA boss J.K. Simmons (a.k.a. Juno’s dad) hasn’t the foggiest idea of what’s going on, but he’s a dab hand at damage control (and though he may not get many lines of dialogue, every one of them’s a zinger).

Sure, it's a wacky lark but much like Clooney’s federal marshall who proclaims never to have discharged his weapon, this one’s a rare misfire from the golden Coens.