This book story of the Mysteries of Paris (French: Les Mystères de Paris) is a novel. The hero of the novel is the mysterious and distinguished Rodolphe, who is really the Grand Duke of Gerolstein (a fictional kingdom of Germany) but is disguised as a Parisian worker. Rodolphe can speak in argot, is extremely strong and a good fighter. Yet he also shows great compassion for the lower classes, good judgment, and a brilliant mind. He can navigate all layers of society in order to understand their problems, and to understand how the different social classes are linked. Rodolphe is accompanied by his friends Sir Walter Murph, an Englishman, and David, a gifted black doctor, formerly a slave.