Sabina Spielrein (Keira Knightley) is the beautiful but sexually disturbed intelligent young woman who throws the complex relationship between Carl Jung (Michael Fassbender), her fledging psychiatrist, and Sigmund Freud (Viggo Mortensen), his powerful mentor, off balance when the married Jung embarks on a sado-masochistic affair with her. Freud and Jung's exchanges are fascinating, a rare glimpse at a seminal moment in the history of psychoanalysis (Freud insisted that sexual repression was the basis of all neurosis while Jung toyed with mysticism). All three actors transform these famous figures into rounded, identifiable people in this lucid, crisply photographed look at the destructive side of human sexuality.