The movie "Black Swan" is about Nina Sayers, a talented but emotionally fragile ballerina in a New York City ballet company. She is chosen to play the dual roles of the innocent White Swan and the dark, sensual Black Swan in the company's production of Tchaikovsky's Swan Lake. While Nina embodies the purity and grace of the White Swan perfectly, she struggles to express the passion and seductiveness required for the Black Swan role. As she competes for the lead, especially with a new rival dancer named Lily who naturally embodies the Black Swan qualities, Nina descends into psychological turmoil, experiencing hallucinations and losing her grip on reality. The film explores themes of duality, obsession, perfectionism, and the cost of artistic excellence as Nina pushes herself to the brink of madness to embody both swans.