David Cronenberg directs this drama based on the relationship between the two founding fathers of psychoanalysis, Sigmund Freud and Carl Jung. The film, which draws from both the stage play, 'Taking the Cure', by Christopher Hampton and the 1993 book, 'A Most Dangerous Method', by John Kerr, also portrays Jung's sexual affair with one of his female patients. Set in early 20th century Europe, the film traces the intense personal and professional relationship between Freud (Viggo Mortensen) and his protege, Carl Jung (Michael Fassbender). When married family man Jung takes in beautiful young Russian patient Sabina Spielrin (Keira Knightley) for treatment at his clinic in Switzerland, she quickly becomes his muse and the two soon embark on a passionate sadomasochistic affair. Meanwhile, Freud and Jung's views and theories are developing in opposing directions, eventually leading to an insurmountable rift between the two.