The queen of the human tribe gave birth to twin girls. Respected by the entire tribe, the older sister Qing Kui, who is gentle and kind, is betrothed to the heavenly prince. The younger sister, Ye Tan, smart and cunning, shunned by her own people, is betrothed to the demon prince. Due to a mix-up, the two sisters are married off to the wrong husbands. It paves the way for two beautiful romances and also ignites a conspiracy that shakes the four realms.