In the prison of San Vittore there is, among other detainees, a strange type that they call "Il Cavaliere". The latter suffers a conviction for theft and his fellow prisoners have a certain respect for him.
A story, set in Rome of 44 A.D., concerning the amorous and political intrigues of the evil Empress Messalina, the wife of the Roman Emperor Claudius, and her eventual hounding to death.