Brandon (Michael Fassbender) is thirtysomething, handsome, and makes a prosperous living as a New York City financial exec. Outwardly to those who think they know him, he's living the dream and has it all figured out. What they don't realize is that he barely functions beyond his monopolizing obsession with sex. He spends his days at the office surfing for porn. He hires prostitutes to come to his apartment at all hours when he's not able to hook up on his own—sometimes in dangerously public places. He is drawn to an alluring stranger with strawberry blonde hair (Lucy Walters) whom he keeps seeing on the subway, and one day follows her at her stop before losing her in the crowd. He appears to predominately be heterosexual, but when push comes to shove he's not even above finding his way to gay bathhouses. Unable to comprehend the nature of intimacy, his interests lie with the strictly carnal as he pushes away anyone who might give an actual damn about him. Eventually, something has got to give.

Unsparingly written and directed by Steve McQueen (2008's "Hunger") and co-penned by Abi Morgan, "Shame" is a notch above the norm where it counts. The general filmmaking aesthetic is austere but dynamic, performances are courageously uninhibited and raw, and Manhattan is evocatively photographed by Sean Bobbitt, sometimes in extended unbroken shots that bleed immediacy. It is a good thing these elements work so well because in lesser hands (and with a great deal fewer full-frontal scenes) it might have come off as a preachy cautionary tale about sexual addiction tailor-made for the Lifetime network. Told through its almost voyeuristic day-to-day study of Brandon's actions, the film does not bother so much with our anti-hero's upbringing or the root to his problems—there is a mention of being born in Ireland and moving to the U.S. when he was thirteen—but on his slick, sleazy, aloof present-day life. No matter what—or who—he does, it's not enough. Like a drug addict, he doesn't appear to enjoy himself, at a low point where he's just going through the motions while battling to keep up an illusion of normalcy.

With the onset of several key events, Brandon is forced into self-reflection mode while heading toward a destructive spiral. After ignoring her umpteenth answering machine message, his younger sister Sissy (Carey Mulligan) shows up to stay with him while she picks up some singing gigs around town. Their relationship is tumultuous and platonic, but there is a nonchalant familiarity with each other and their bodies—Brandon thinks nothing of holding a conversation with her while she stands wet and naked in the shower—that suggests it might not have always been that way. When Sissy meets Brandon's philandering boss and confidante David (James Badge Dale) and they sleep together, Brandon is angry and, perhaps, a little jealous.

Meanwhile, he finds himself on a date with friendly, vivacious co-worker Marianne (Nicole Beharie). She's clearly interested in him, but can't quite believe it when he honestly tells her he doesn't believe monogamy is possible and thinks romantic entanglements are silly and pointless. Against her better judgment, Marianne goes through with a sexual encounter during their lunch break—maybe she thinks she can change him—but it only ends in disappointment and resentment, squashing any chance she and Brandon might have had. It's also the first time when Brandon isn't able to perform, so to speak. By this point, Marianne has become all too real for a man who specializes in fantasies.

Quite possibly the male equivalent of Jessica Chastain, Michael Fassbender has seemingly come out of nowhere in 2011 and situated himself as one of the most exciting new actors in film. In "Jane Eyre," "X-Men: First Class," and now "Shame," he has taken over the screen with the command, conviction, and smoldering charisma of someone who has been on the A-list for decades. Here, especially, he has received his most bare and searing challenge, portraying a man the viewer wants to watch but doesn't necessarily like or agree with. Like a brutal car accident, it is difficult to turn away from him. What he has accomplished, however, is no mistake. Fassbender is unapologetic in the depths he plunges; it is kind of, well, a shame that Brandon isn't written with the encompassing depth the actor gives him.

Carey Mulligan (2011's "Drive") has a smaller but critical role as Sissy, tearing it up with an alternating airy light and plaguing darkness. Indeed, like her brother but in an entirely different way, there is more to her than initially meets the eye. When Mulligan performs a down-tempo rendition of "New York, New York" at the lounge she's singing at, the camera holds on her for virtually the whole song. Mournful and gorgeous, it's enough to stagger. No wonder Brandon can't help but wipe away a tear after. Also excellent, Nicole Beharie is the down-to-earth beacon that at least partially drives Brandon to reassess his life. Her Marianne is a woman anybody would be lucky to nab, and Brandon sees that. It's the thing that scares him most. With just a few scenes, Beharie is unforgettable, keeping up with Fassbender's intensity by playing it lighter and, ultimately, more poignantly.

"Shame" is uncompromising, no doubt, but the picture doesn't add up to as much as the viewer hopes based on the clear talent involved. By its nature, Brandon has two choices: go about his days as he has and pay the tragic toll, or make an effort to right the mistakes he's made and seek professional help. For 101 minutes, "Shame" intrigues and rattles, but is mostly predictable and a little too contrived by the end. Take away the sterling acting turns and silky directorial control and its trajectory isn't all that different from an issues-laden, message-heavy television melodrama one can envision Dean Cain starring in. Cain, by the way, is a fine performer in his own right—better than most of the projects he receives. If there is no surprise in where "Shame" is going, it still provides a vigorous jolt to the system.