This is a remake of Kim Ki-Young's 1960 film with the same title. The original film can be watched for free here. The story is about what happened after a housemaid got pregnant by the master of the house. The wife had a young daughter and was pregnant with twins at the same time.
Liked the nice soundtrack and beautiful choreography of the sex sequences of this film but the original film was more exciting in terms of the suspense and thriller portion! Half expected the old maid's son would play a part in the maid's revenge but was disappointed.
Internet Movie Database Link