Dante arrives at the castle of the recently deceased Marquis Zanetti to sell a book which contains a prophecy that the death of nine members of the Zanetti family will reveal a hidden treasure.

The aging villain Émile Morland talks his old friend Aristide into helping him with to kidnap the son of a millionaire.

A young restorer is commissioned to save a fresco representing the suffering of St. Sebastiano, which was painted on the wall of a local church by a mysterious, long-dead artist.