The Icelandic Psychological Association has prepared a test. They call it a sensitivity assessment – a way of measuring a person’s empathy. It is, they insist, merely a tool for identifying people who need extra resources. People with moral disorders. People who are likely to offend. 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 Olafur – find themselves caught in the teeth of the debate.