Fingersmith:

No one and nothing is as it seems in this Dickensian novel of thrills and reversals. Sue Trinder is an orphan, left as an infant in the care of Mrs. Sucksby, a "baby farmer." Mrs. Sucksby’s household also hosts a transient family of petty thieves--fingersmiths--for whom this house in the heart of a mean London slum is home. One day, the most beloved thief of all arrives--Gentleman, an elegant con man, who carries with him an enticing proposition for Sue: If she wins a position as the maid to Maud Lilly, a naïve gentlewoman, and aids Gentleman in her seduction, they all will share in Maud’s vast inheritance. With dreams of paying back the kindness of her adopted family, Sue agrees to the plan. Once in, however, Sue begins to regret her decision.