Ouroboros mystagius is perhaps the most ancient and powerful artifact on earth. They say that the first ouroboros was made by Satan himself, putting into it ancient magic and the black malice of his heart. Then his students and servants created several more such artifacts, and each of them has amazing power - returning youth to its owner. What is mysticism? Prejudice? Or something more mysterious and inexplicable? The key to solving the mystery is hidden in an ancient painting by an unknown Italian master, which St. Petersburg restorer Dmitry Starygin is working to recreate. Trying to penetrate the secret, he sets out on the trail of one of Satan’s faithful servants. The book was also published under the title “Testament of an Alchemist.”