Secret of the Sultan (Turkish: Sultanın Sırrı) is a 2010 Turkish action film, directed by Hakan Şahin and written and produced by historian and journalist Ömer Erbil, starring Emanuel Bettencourt as an American professor in Istanbul to search for the sultan's mysterious chest in the hidden underground cloisters of the Topkapı Palace with the help of his friend Mark Dacascos.

The film, which went on nationwide general release across Turkey on 17 December 2010 (2010-12-17), was made with the support of the Turkish Ministry of Culture and Tourism and the Istanbul 2010 European Capital of Culture Agency.

It was described by Hürriyet Daily News reviewer Emrah Güler as a mixture of the "National Treasure" movies and Dan Brown's "The Da Vinci Code" and "Angels & Demons"[1][2] An American professor travels to Istanbul to find a mysterious century-old chest built by Sultan Abdülhamid II, which he believes is relevant to the present political power games over oil.

His search leads him discover long-forgotten underground cloisters at Topkapı Palace, now the Topkapı Museum, where he confronts a patriotic museum curator and the Turkish intelligence.

[1] The film premiered at a gala screening, attended by star Mark Dacascos, at Istinye Park, Istanbul, on 9 December 2010 (2010-12-09).