Every week, men and women suffering from pain come to see Dr Danzinger at the Pitié-Salpêtrière hospital in Paris. He listens to them, advises them and tries to relieve the pain that keeps them under its yoke and that he devotes his research to. One day, he listens to Alain Bastien who following a motorcycle accident no longer feels any pain. After an initial series of tests, Dr Danzinger notices that Alain Bastien indeed feels the pain, however it no longer affects him; he has become indifferent to it. The doctor immediately catches a glimpse of the enormous possibilities that open up for understanding and treating pain. Together with Alain Bastien, he embarks on a long series of tests that are expected to eventually enable him to offer a radically new interpretation of the mechanisms of pain and to look at new methods of treatment. It is this passionate scientific quest that this documentary shows. The medical investigation we follow gradually offers us an in-depth look into the meaning and role of pain in our lives. The role is much more complex than at first sight. Evidence of this is that Alain Bastien, by losing the feeling of pain, seems also to have lost the ability to feel emotions and therefore slowly becomes isolated from the world. What if pain were an essential trait of the living?