Nina Sayers, a young dancer with the New York City Ballet, is overwhelmed by immense pressure when she finds herself competing for the lead role in Tchaikovsky's "Swan Lake." As Nina navigates her demanding rehearsals and grueling performances, she begins to lose her grip on reality, descending into madness. With Mila Kunis as her rival Lily, a physical resemblance to Nina but an uninhibited quality she lacks, Nina's hallucinations grow more severe, leading to a confrontation with her own dark alter ego. As the ballet's opening night approaches, Nina must confront the line between reality and fantasy, self-destruction and perfectionism, in this psychological thriller about the cutthroat world of dance.