The feud between Sigmund Freud and Carl Jung, the fathers of modern psychoanalysis, provides the backdrop to this deceptively intelligent and sexually charged chamber piece. Freud, however, is more of a third wheel here, since the film deals mostly with the affair that develops at the turn of the 20th century between the idealistic Dr Jung (Michael Fassbender) and Sabina Spielrein (Keira Knightley), a hysterical patient who becomes his assistant, then his mistress, then his peer. The film's stage origins show, and Knightley isn't quite up to carrying such a demanding role, but there's a lot to chew on in the script by Dangerous Liaisons scribe Christopher Hampton. It may seem an odd choice for David Cronenberg, director of The Fly and other visceral horrors, but, at its core, there's a provocative story lurking here about the delicate and fragile dividing lines between mind, body and soul.