Gaustad Psychiatric Hospital in Oslo. At dawn on a cold winter day, one of the patients is found strangled to death. His mouth is open in a silent scream. Police Inspector Sarah Geringen, who arrived at the scene, immediately realized that she was faced with a case out of the ordinary. Questions arise one after another: what is this strange scar in the form of the number 488 on the victim’s forehead? Where did the ominous drawings on the walls of the hospital room where he was kept come from? Why does the hospital management have almost no information about the identity of the man who spent more than thirty years there? Thus began an intricate and extremely dangerous investigation for Sarah, which will force her to travel around the world a lot: Paris, London, the volcanic Ascension Island, abandoned mines of Minnesota, Nice... Her partner will be the French journalist Christopher Clarence, with whom she will have to discover the stunning truth that was buried in top-secret laboratories.