The Ache (2009)

A young Chinese-Canadian woman, Sheri, has been told by her mother that for the past ten years, their family has been cursed by an evil spirit. One day, Sheri discovers what she understood was a ghost assaulting her family, is a real woman who is having an illicit affair with her father. Upon further investigation, Sheri starts to realize there is something very strange about this woman. She is an entity from another world who has become trapped in our world by the passion of her relationship with Sheri's father.