Nina (Natalie Portman) is a ballerina whose passion for the dance rules every facet of her life. When the company's artistic director decides to replace his prima ballerina for their opening production of ``Swan Lake,'' Nina is his first choice. However, Nina has competition: Lily, a newcomer. While Nina is perfect for the role of the White Swan, Lily personifies the Black Swan. As the rivalry between the two dancers transforms into a twisted friendship, Nina's dark side begins to emerge.