With a small set of characters and shot at only a few locations, A Separation is the kind of moral minefield of a movie that one expects is based on a play - but it isn't. Written and directed by Iran's Asghar Farhadi, it won the Golden Bear at the Berlin film festival and is the official Iranian candidate for the Best Foreign Language Film at next year's Academy Awards. The highly charged drama is best seen with as little prior knowledge of its plot as possible - know this, though: you're unlikely to see a finer film all year. A Separation follows Nader (Moaadi), who has a father suffering from Alzheimer's and in need of round-the-clock care. When his wife, Simin (Hatami) makes plans for the pair and their teenage daughter to leave the country for a better life, Nader refuses because his father is too unwell to go with them. Simin then takes an extreme course of action and separates from her husband (hence the film's title). But the family's problems really begin when Nader hires Razieh, a young, pregnant, devoutly religious woman to look after the home and care for his father while he goes out to work. When he suspects she has been neglecting her responsibilities, a fierce showdown between the two in his Tehran apartment kick-starts a painful battle that could have terrible consequences for both. The film forensically examines the morality of mistruth between loved ones in a way that feels as original as Woody Allen's Crimes and Misdemeanours - although it reaches a very different conclusion to the US filmmaker's black comedy. With finely tuned performances (not least from the film's two young actors) and not a single word of dialogue wasted, A Separation's incredible moral, social and psychological complexity is utterly absorbing.