After her father's death, young Frenchwoman Ellen Tibaud arrives in the Bulgarian village of Gradishte, led there by the mysterious founder of their family and renowned katar-bogomil, Robert Burg. All that he left behind was a parchment filled with incomprehensible signs and letters in the form of drawings. It is up to Ellen to decipher his message to his grandchildren and the world. In her search, she meets Father Peter and adventurer Victor, who has been searching for the manuscript of "The Sacred Book of the Bogomils" for some time. The relations that develop will change everyone.