The Coen brothers may have achieved mainstream success with their Best Picture Oscar for No Country for Old Men, but so much for adapting prestigious literary novels that engage the essential American archetypes; they are back with another twisty, genre-tweaking movie filled with their trademark combination of deadpan delivery by characters who are venal, dumb, or both, plus some shockingly grisly violence.

In past films, the Coens have played on the fine line between being derivative and being clever in adapting genre conventions to shaggy-dog-style discursive plot lines and with the way an understated tone can give an ironic twist to an under-written wisecrack. This movie skates along that fine line but benefits tremendously from two character actors who are usually limited to leading man roles because they happen to be People Magazine Sexiest Men of the Year.

George Clooney plays Harry, a twitchy, slightly anxious, persistently polyamorous U.S. Marshall from the Treasury Department. When he mentions twice that he has never discharged his weapon, we know that gun is going to have to go off before the end of the film. Brad Pitt plays Chad, a dim but energetic personal trainer who is enthusiastic about hydrating, always has his earphones in, doesn’t like wearing a suit, and thinks he’s hit the big time when a computer disk with some spy-ish looking numbers is found in the ladies’ locker room of the health club. Chad finds out that the data belongs to Osborne Cox (John Malcovich, furiously hostile as only John Malcovich can be) and thinks he might be able to get a “reward” for returning it. When Cox doesn’t cooperate, Chad and his colleague Linda (Frances McDormand), who desperately needs money so she can get liposuction, decide to find another buyer. But they are so clueless about international affairs that the only country they can think of to sell it to is Russia. They drive over to the Russian embassy and ask the first person they meet there if he wants to pay them for it, promising (without any basis in reality) that there is more where it came from.

Meanwhile, several of these characters run into each other when they are — let’s just say looking for love in all the wrong places. And out at Langley, a senior CIA officer briefed on the situation (J.K. Simmons of “Juno”) orders that the FBI be kept out, a body in question be “burned,” and that he get an update “when it all makes sense.” That will be a long wait.

The real fun here is seeing the wickedly comic deftness of Clooney and Pitt, liberated from the burden of glamor and clearly enjoying themselves tremendously. Tilda Swinton is nicely steely as Cox’s doctor wife, Richard Jenkins is endearingly timid as the lovelorn manager of the health club, and McDormand delivers as the relentlessly positive believer in the infinite possibilities of self-improvement. There are some lightly touched themes of delusion, “negativity,” and looking for love in all the wrong places that might be a glimpse of a larger statement about world affairs. But we can’t be expected to unpack all of that for at least a decade. In the meantime, those who are looking for a return to the confounding archness and stylized dryness from the minds of the Coens will enjoy this latest peek into their view of the world.