At first glance, the head of the university library fell deadly while passing over a railing. Quickly, it becomes obvious that there was premeditation and that it is therefore a murder. But at the material time, he was not supposed to be in his workplace. Was the assassin targeting someone else ? This unfortunate coincidence made it possible to reveal in broad daylight a secret that the librarian had been hiding carefully for years... The team understands that the victim, married and father of a child, is not at all who he claims to be. Years ago, he would have left his old life and changed his identity. Would his death have anything to do with this discovery ?