The Isle of Zorda.

Sarkani, an adventurer, finds a trusted carrier pigeon, takes possession of the code message and, teaming up with the unscrupulous banker Torenthal, gets the position of secretary from Matthias Sandorff. After deciphering the message, he discovers a conspiracy against the government. By law, Thorenthal and Sarkani receive half of Sandorff's fortune. His kidnapped daughter was raised by Thorenthal as his own child, and in order to keep her share of the fortune, he tries to marry her off to Sarkani, but she is in love with the son of one of Sandorff's friends and refuses. Sandorff takes over the fisherman who betrayed him, as well as the banker who lost his fortune in Monte Carlo. Together with Sava's beloved, whom he cured, they save Sava and take Sarkani into their own hands. Sandorf surrenders them to the legitimate authorities, unites his daughter and her lover, and everyone lives happily on the island of Zord.