Thriller

Henri de Castelrock, whose father has been forced into exile after having married a circus horserider, comes back to reclaim the family property, in an eerie atmosphere. There he finds a mysterious letter and begins to investigate a story of kidnapping. He meets the family skeleton hidden next to the library, who helps him in his detective work. Some clues lead him towards a circus, where he rescues his cousin before taking off with her.

The incidents of the story are laid in Rome. Herman. a lion tamer, and Cleo, his assistant, are the leading figures of a circus that is showing in one of the great Roman amphitheaters.