Artur Riegerbaum is searching for the lost 15th part of the Corpus Hermeticum, written by Hermes Trismegistos, the father of all magicians, mystics, and philosophers. The work was once in the library of the world-famous opera diva Emma Destinn, and later in the possession of Prague lawyer Karel Hartmann, who perished in the Holocaust. In his search for the book, Artur comes across clues on Prague's house walls—and questions about the nature of reality: Is it what we perceive, or merely a product of consciousness? Between his rational world as a lawyer and the mysterious hunt for the book, he is accompanied by a learned, strange friend. Which of the two worlds is more real?