After being betrayed by her boyfriend Lu Chengyuan and left with nothing, Su Li inherits a run-down cottage from her estranged aunt. She discovers that her aunt had been labeled a "madwoman" for investigating the drowning death of her son, and had left behind hidden evidence. With the help of her friends Fang Xiaotang, Cheng Yanqiu, and Jiang Ye, Su Li unravels the Gu family's two-decade-long conspiracy to cover up the truth—involving industrial pollution, bribery, and murder—ultimately bringing Gu Yanzhou to justice. She transforms from a dependent "mistress" into an independent, resilient woman, putting down roots at the Lilac Cottage and finally achieving justice for her aunt.
