As portrayed by Michael Fassbender (“X-Men: First Class”), Brandon is a sex addict. When he’s not engaging in sexual activity with strangers, he’s downloading porn on his computers at home and the office. Work, sex, work, sex, work, sex — that’s his existence.

Then his emotionally wounded sister (Carey Mulligan, “Drive”) has to upend said rituals by temporarily moving into his apartment.

Finally opening Friday at AMC Quail Springs Mall 24, “Shame” may carry the dreaded NC-17 rating, but don’t mistake it for the very thing with which Brandon is obsessed. A film can be adult in nature without being an “adult film” (the intent behind NC-17’s controversial creation in 1990), and British director Steve McQueen’s follow-up to his acclaimed “Hunger” makes a strong case for that fight.

As a stark, sterile look at a dirty young man, this is as finely crafted a work as you may see all year, yet its subject matter will result in many a walkout — perhaps from the first scene, in which Fassbender goes full-frontal nude.

His bravery in doing so is only a small part of what makes his Oscar-worthy performance the most fascinating among all actors in 2011. The guy commits to a part that, in lesser hands, could kill a career, and refuses to shy away from the most problematic material.

It may make you feel uncomfortable; in fact, it should. The most challenging — and potentially rewarding — films do.