Preah Peay Phat(1971)

A peasant, Chivon, played by Kong Som Eun, falls in love with the daughter of a wealthy man, "Preah Peay Phat", Vichara Dany. Chivon does everything he can in order to get his lovers attention but they are forbidden to see each other. When the peasant falls in love with another woman, Preah Peay Phat is heartbroken. That is when the terrible news is revealed, Preah Peay Phat and Chivon are brothers and sisters.