Abandoned unconscious by Dorian in the beach house in Ostia, Inspector Gori is rescued by her colleagues. Upon awakening from a concussion, the woman discovers on her body a mysterious tattoo given to her by Dorian. While the inspectors are looking for the lighter with the mole's prints lost by Gori on the beach in Ostia, Commissioner Benvenuti becomes convinced that the mole is the magistrate Castelli. The analysis of the Russian mole's footprints exonerates the magistrate Castelli and reveals the true identity of the secret informant: Katarina Kasparova, the girl long sought by Inspector Gori and then believed to be dead. The magistrate recognizes her as his governess from the East, Maria, and thanks to her testimony the inspectors of the X will be able to find Dorian's traces.