In a dim spotlight on a small stage in a smoky Greenwich Village club, Llewyn Davis has just sung his final number, the twangy traditional "Hang Me, Oh Hang Me." The applause is enthusiastic, but the look on Davis' face shows only a trace of satisfaction. If he got paid for the gig, it was pocket change, and if he's sleeping somewhere tonight, it's on somebody's couch.

The hero of Joel and Ethan Coen's Inside Llewyn Davis, a sublime odyssey to nowhere, hunches his shoulders against the cold - or just against the cruelties of life - and carries on. The year is 1961, when a few dingy cafes hosted hootenanny nights, and a few intrepid troubadours finger-picked old blues riffs and mountain songs on their battered guitars. But the folk explosion that came in with Bob Dylan and Joan Baez and Phil Ochs was still a ways off, and, for the likes of Llewyn and his kin, almost unimaginable.

Inside Llewyn Davis plays like some beautiful, foreboding, darkly funny dream. Oscar Isaac, who stars as Llewyn - soulful, sardonic, with a beard and a head of tangled black curls - has been memorable in supporting turns (the snowbound "Outcome" agent at the beginning of The Bourne Legacy, Joseph in Catherine Hardwicke's The Nativity Story), but what he does here, in a role that has him on screen in almost every frame, is remarkable.

Isaac's hardluck balladeer is always in the wrong place at the wrong time. Even when he catches a break - like the recording session his friend and fellow folksinger Jim Berkey (Justin Timberlake) sets up at Columbia Records - something bad is bound to happen. (Note to novice recording artists: Sign the contract with the royalties clause.)

Isaac, as Llewyn, is sad-eyed and simmering. He is not the most upright or likable of men, as Jean Berkey (Carey Mulligan), his friend's wife and another singer on the scene, is quick to inform him (with good reason). But when he picks up the guitar and starts to sing, all the bitterness and bruised ego melt away. Isaac does his own singing and playing - and these talents, too, are a revelation.

Inside Llewyn Davis has much in common with earlier Coen Brothers affairs, especially Barton Fink, their 1991 tale of another coulda-shoulda-woulda figure adrift in a colorful milieu, a playwright trying to make it in early-'40s Hollywood. John Goodman shows up as an ominous sidekick in that one, and he's in Inside Llewyn Davis, too, as a gruff jazzbo, when Llewyn bums a ride with him and a Kerouac-ian Garrett Hedlund to Chicago for a big audition.

There are other cool cats in Inside Llewyn Davis, and one real-life red Mackerel cat, too. The feline, which Llewyn is forced to temporarily adopt when he locks it and himself out of a couple's apartment, becomes a traveling companion, and a totem. And just maybe that red Mackerel is a red herring. Whatever the cat represents, it is responsible for one of the film's most indelible exclamations.

The first time I saw Llewyn Davis, about a month ago, I was ready to put the movie somewhere in the middle of the Coens' amazing canon, not up there with the reverberating strangeness that is Barton Fink, not the deadpan and macabre masterpiece that is Fargo, not the bloody, fateful saga of No Country for Old Men or the stoner Chandlertown noir of The Big Lebowski. But the second time around, Inside Llewyn Davis seems trickier, more imbued with meaning and melancholy.

This isn't simply an affectionate look back at a mythologized era. (The Coens used The Mayor of MacDougal Street, a memoir by the great gravel-voiced folk sage Dave Van Ronk, for inspiration and a couple of plot twists.) It's a story of artistic struggle, of dumb luck and bad luck, and of the crushing beauty that can be wrested from a song.

One chestnut that isn't part of Llewyn's onscreen repertoire, and does not appear on the Coen Brothers' soundtrack (assembled with the help of that Americana music maestro T Bone Burnett), is "Will the Circle Be Unbroken." As a taxi screeches into the Greenwich Village night - the last image in Inside Llewyn Davis - it would have been the perfect closing number.

Too perfect. Which is why the song does not appear.

Inside Llewyn Davis **** (Out of four stars)

Directed by Joel and Ethan Coen. With Oscar Isaac, Carey Mulligan, Justin Timberlake, and John Goodman. Distributed by CBS Films.

Running time: 1 hour, 45 mins.

Parent's guide: R (profanity, violence, drugs, adult themes)

Playing at: Ambler Theater, Ritz East, and Carmike at the Ritz Center/NJEndText