The Icelandic Psychological Association has prepared a test. They call it a sensitivity assessment: a way of measuring a person's empathy and identifying the potential for anti-social behaviour. In a few days' time, Iceland will vote on whether to make the test compulsory for every citizen. The nation is bitterly divided. Some believe the test makes society safer; others decry it as a violation. As the referendum draws closer, four people - Vetur, Eyja, Tristan and Ólafur - find themselves caught in the teeth of the debate. Each of them will have to reckon with uncomfortable questions: Where do the rights of society end and the rights of the individual begin? When does utopia become dystopia?