In one of the universities of the Sorbonne, a miniature was stolen that served as the cover for a treatise by the little-known author Vasalis. All that is known about the author is that for his scandalous work he was executed under Pope Clement IV. The legend of the treatise has leaked through the centuries, and the name of its author has become a symbol of intellectual freedom. The scientist, who devoted his whole life to the search for the mysterious treatise, unexpectedly committed suicide. During the census of the book stock, three more rare, irreplaceable books are discovered missing. Material damage - half a million euros. The disappearance of the books is accompanied by a number of mysterious events and the death of people. The detectives come to the attention of a university teacher and a wealthy bookseller. The investigation that has begun leads to completely unexpected results...