In Victorian London, after his life is saved by a young physician, a thief utilizes the knowledge he gains in prison and from the scientific lectures he attends as the physician's case study exhibit to create a new, highly successful, double life for himself.

After twenty years as a gentleman, Montmorency is glad to be free of Scarper, his wretched alter-ego, but when a young friend is caught in the middle of a murderous political plot, Montmorency may have no choice but to call upon Scarper for help.