Having lived half his life in America, Frenchman Damien Louvel returns to his homeland after learning of the sudden death of his father. Here he discovers that Louvel the Elder has devoted many years to researching a mysterious relic - the Jorden Stone - whose two-thousand-year history has linked together the destinies of the first Christians, the Templars, the Freemasons, Leonardo da Vinci and Napoleon. It soon becomes clear that it was these studies that cost the historian his life, but Damien still decides to continue them.