Who did Nina attack when he kissed her?
Nina Sayers is a 28-year-old dancer in a New York City ballet company, which is preparing to open its new season with Tchaikovsky's Swan Lake.  With prima ballerina Beth MacIntyre being forced into retirement, artistic director Thomas Leroy announces he is looking for a new dancer to portray the dual role of the innocent White Swan and the sensual Black Swan.  Nina auditions for the role and gives a flawless performance as the White Swan, but fails to embody the Black Swan.
The following day, Nina asks Thomas to reconsider choosing her to play the role.  When he forcibly kisses her, she bites him before running out of his office.  Later that day, Nina sees the cast list and discovers, much to her surprise and that of her overprotective mother Erica, she will be portraying the lead.  At a gala celebrating the new season, an intoxicated Beth confronts Nina, accusing her of sleeping with Thomas to get the role.  The following day, Nina discovers that Beth was hit by a car while walking in the street and Thomas believes she did it on purpose.
During rehearsals, Thomas tells Nina to observe new dancer Lily, whom he describes as possessing an uninhibited quality that Nina lacks. Nina also falls victim to several hallucinations of a doppelgänger following her wherever she goes and finds unexplained scratch marks on her back. One night, Nina accepts Lily's invitation to dinner despite Erica's objections.
Thomas