A pianist about to flee from a duel receives a letter from a woman he cannot remember. As she tells the story of her lifelong love for him, he is forced to reinterpret his own past.

The likeable and carefree Grand Duke of Abacco is in dire straits. There is no money left to service the State’s debt; the main creditor is looking forward to expropriating the entire Duchy. The marriage with Olga, Grand Duchess of Russia, would solve everything, but a crucial letter of hers about the engagement has been stolen. Besides, a bunch of revolutionaries and a dubious businessman have other plans regarding the Grand Duke. With the intrusion of adventurer Philipp Collins into the Grand Duke’s affairs, a series of frantic chases, plots and counter-plots begins.