Shen Qingyuan, the legitimate daughter of the Duke of Zhenguo's household, is switched at birth through a malicious scheme and raised as an orphan in the countryside. From childhood, she and her frail younger brother depend on each other. Sixteen years of hardship teach her how to survive in the mud, while she secretly inherits her family's medical and poison-making arts and develops remarkable courage. Through her own efforts, she raises her little brother to adulthood.
By a twist of fate, the truth about the baby swap finally comes to light, and Shen Qingyuan is brought back to the Duke of Zhenguo's household. But returning home is no easy path. The adopted daughter, Shen Mingyue, has enjoyed the privileges of a legitimate daughter since childhood and earned the duke and his wife's affection. Seeing Shen Qingyuan's return as a threat to her position, she burns with jealousy and secretly joins forces with people inside and outside the household to set a trap for her: accusing her of stealing the family's treasures, spreading rumors that she is crude and uncultured from her country upbringing, and even slipping slow-acting poison into her food in an attempt to drive her out for good.
Though new to the noble household, Shen Qingyuan is not the least bit timid. She sees through Shen Mingyue's schemes one by one, using the resilience and ingenuity she developed in the countryside to turn the tables. Not only does she prove her innocence, she also exposes Shen Mingyue's hypocrisy, gradually winning the support of the household's old retainers and some of the clan. Along the way, she meets Crown Prince Xiao Yi, who is mistrusted because of political rivalries at court. Xiao Yi admires Qingyuan's intelligence and integrity, while she respects his ambition and sense of responsibility. From mutual suspicion to trust, they forge a strong alliance.
Qingyuan uses her medical and poison-making skills to save the crown prince from repeated assassination attempts and her keen insight to help him root out corrupt officials. In return, the crown prince stands up for Shen Qingyuan, helping her secure her place in the duke's household and uncover the political conspiracy behind the baby swap. Together, they navigate household rivalries and political intrigue with care, and fight to turn the tide amid the shifting currents of court politics...
