Soiinthanin is a beautiful, smart, well-educated girl, who is the daughter of Saengfah, who owns the "Yupharet" house. But because her mother is only a mistress, and she is an illegitimate child, she spends her life in their house being oppressed and not experiencing the same privileges her half-sister Soifah gets.The miserable and painful life of her mother is not lost on her as she too finds herself facing the same fate when she falls for Soifah's fiance Phas, a man who has to marry her half-sister in order to maintain his noble family's honour.