The maid Lan Yuan celebrates her sister's wedding and marries into the Pei Mansion; on her wedding night, she discovers the body of her former mistress Su hidden under the bed; Lan Yuan is horrified but dare not speak out, so she can only investigate secretly; she discovers that three people in the Pei Mansion There was a fierce fight in the house, and the death of the former mistress was suspected of poisoning; the young master Pei Xuanyin was unconscious and was suspected to have been poisoned by the second house; Lan Yuan and the maid Qiu Tang teamed up to find a secret room in the Pei Mansion, which contained the account book and letters; the second wife intended to seize the legitimate son, but the housekeeper secretly controlled it; Lan Yuan approached Pei Xuanyin and found that he was conscious but pretending to be comatose; the two formed a secret alliance, gradually uncovering the conspiracy between the Pei family and the powerful people in the capital; Lan Yuan's life experience gradually came to light, and she was actually the lost niece of the Su family; in the end, the truth was revealed, Pei Xuanyin woke up and took power, Lan Yuan regained his identity and chose freedom
