The Third Prince of the human race, determined to uncover the truth behind his eldest sister's disappearance, chooses to disguise himself as a woman and take his younger sister's place in a political marriage. The "husband" he must face is the bloodthirsty Beastman Crown Prince, Ming Sheng. To buy time for his investigation, Lu Mi plays the role of a deeply infatuated princess, meticulously studying the Prince's preferences and professing his love in increasingly creative ways. Meanwhile, Ming Sheng—discriminated against due to his "impure" bloodline—uses the mask of a tyrant for protection. Though he had intentionally terrified all previous suitors away, he unexpectedly encounters Lu Mi, who refuses to play by the rules. Having never been truly loved, Ming Sheng gradually loses his composure, revealing his weaknesses under Lu Mi's feigned yet burning "affection."