The Housemaid (2010)

Eun-yi is a playful young woman, a good match for a job as nanny to a precocious child, Nami, the daughter of a wealthy couple, Hae-ra and Hoon. Hae-ra will soon have twins as well. The majordomo, Mrs. Cho, is the household's cold stone center. Before long, Hoon seduces Eun-yi, and when Mrs. Cho tells Hae-ra's mother about the affair, Eun-yi is up against women with wealth, power, and no conscience. Can Eun-yi maintain her dignity and perhaps even put the family in their place?