To infect the reader, a few strokes are enough for Scerbanenco. Already the initial, dry and concise presentation of the Steve family is enough to intuit that crime, which is announced as a drama product of fanaticism, is inevitable. Its members, all lovers of the theoretical and practical aspects of the moral sciences, live monastically in a miserable house in the suburbs: the cave of the philosophers. It is Luciana who disappears one night and is later found dead on the bank of a river not far from the corpse of a rich industrialist who had decided to protect her. A difficult and intricate case for Arthur Jelling, whose knowledge of the human soul and intuition will lead him, little by little, to discover the most secret truth.