Fingersmith

Raised by a loving family of thieves, orphan Sue Trinder is sheltered from the worst of the Victorian underworld until it becomes her turn to make the clan's fortune. She must help a professional rogue named Gentleman marry an heiress and then steal the girl's inheritance by declaring her insane. Sue wants to please everyone, but as she's confronted with the seemingly helpless victim, Maud, she begins to have her doubts.