In London in 1903, during a reception at the German embassy, the legendary swindler Rocambole, thought to have died in the penal colony, helps the British secret service compromise a Prussian diplomat. His mission completed, Rocambole, under the identity of the Comte de Chamery, returns to Paris, where Baron Keller, an arms manufacturer in the service of the Kaiser, entertains the famous prima ballerina Cléo Santelli at Maxim's every evening, with whom he is madly in love. Despite her attentions, the young dancer falls in love with the false Chamery, who seems to have sworn the Baron's doom and ridicules him in the salons.