Joel and Ethan Coen are becoming legendary for their gritty, Oscar-stealing melodramas (“”Fargo,”” “”No Country for Old Men””) and their off-kilter, cult-classic comedies (“”The Big Lebowski,”” “”Raising Arizona””). Their newest endeavor, “”Burn After Reading,”” will unfortunately become neither.

Commanding an all-star cast led by George Clooney, John Malkovich, Brad Pitt, Frances McDormand and Tilda Swinton, “”Burn”” should be money in the bank for the Coens. But as Pitt’s dimwitted character will struggle to tell you, “”Appearances can be deceptive.””

The narrative focuses mainly on Linda Litzke (McDormand), a manager at a Langley, Va., fitness center. She and coworker Chad (Pitt) discover a CD containing what appears to be classified government files that were misplaced by ex-CIA agent Osborne Cox (Malkovich). The unscrupulous gym employees attempt to blackmail Cox, but their total ineptitude results in the sort of dark comedy and unexpected violence that has become iconic of Coen films.

The initial 20 minutes were almost difficult to sit through, bulging with exposition and more romantic entanglements than 20 minutes of MTV. The quirky characters save the slow plot. Laughs are few and far between until the simpleminded Chad becomes a main player in the twist-turning spy caper that unfolds. Clooney and Malkovich play wonderful CIA rejects, sporting beautiful personality defects to play off of Swinton’s cold, hard bitchiness.

The underwhelming beginning eventually leads to a twisted, tragicomic climax in which the film inadvertently mocks itself for being little more than a puzzling jumble. The characters are brilliant, but the slow plot will drive away anyone not already committed to the gospel of the Coens.