Brandon is a good-looking, elegant man with a dark, hidden sex addiction that is slowly consuming his being. He lives to have sex with paid prostitutes, married ladies, co-workers, everywhere, anytime, and when he hasn't got the chance to do it with a woman, he masturbates or has a man go down on him. He has a sickness that prevents him from ever smiling, ever feeling any genuine joy or building a relationship with anyone. As dirty his mind is, as filthy his sex encounters may seem, he lives in an immaculate, sterile apartment, always well-dressed and well-mannered, with an impeccable look. His past is irrelevant up to a point, his needs are only sex-related, he lacks affection or any reaction. His routine is challenged by the arrival of his dysfunctional sister, Sissy, who seems to have a history of suicide attempts, a sadness and loneliness that makes her throw herself in the arms of any man, including Brandon's married boss, David. She is her brother's opposite: messy, sloppy, needy, frail. But she is more open to acknowledging her mistakes, to talking about her past or to sharing her need for human affection.
Both Brandon and Sissy feel ashamed of their past and their becoming as adults, though their approaches are different; when feeling overwhelmed and abandoned, Sissy cuts her wrists and Brandon's angular features and icy gaze melt down and his inner pain and frustration burst to the surface. He collapses to the ground, in tears, facing for the first time, his futile existence. Their performances, both Brandon's and Sissy's, make the movie unforgettable in a sad, painful way. There is a combination of cold, chiseled features, a penetrating pair of blue eyes and a sensitive, mutilated soul that make Michael Fassbender a vibrant actor and Carey Mulligan's impulsive, self-destructive acting is almost heart-breaking. The scene where she gives such a slow, poignant performance of New York New York, filmed in a long shot, is going to stay with the viewer forever; it is one raw moment of honesty that moves Brandon to tears and binds them forever.
I believe the movie is challenging in rendering the idea that promiscuity is bound to lead to unhappiness whereas monogamy is the key to a blissful life. As a matter of fact, Brandon's addiction is the one thing hindering him from feeling good about himself and the shame he feels comes from the pressure of the social norms; he is only a freak to the extent of being turned into one by judgemental eyes such as David's, his co-worker's or even Sissy's. Shame is neither a celebration of free sex, nor a crucifixion of a man's lifestyle; it is rather what makes the "addiction" itself that needs to be considered. How is Brandon different than his boss David? The latter is married, therefore socially safe and allowed to fool around under the patronage of the marriage institution, whereas Brandon is a pariah for not being able to control an addiction that makes him, deviant and his boss, normal.
Pain is portrayed in shades of grey and blue, from clothes to rooms, the classical soundtrack is rich, cold and stylish and the close-ups go deep into the characters' souls, capturing their innermost feelings. The city itself adds up to the hollow, sad looks of the characters and appears to be as cold-hearted as life itself. It is a world of lost souls trying to connect but failing in reaching one another.