In her previous life, Gu Zhaoning watched helplessly as her mother was driven to death by her father's favored concubine, her younger brother was schemed against and died young, and she herself was used as a pawn before meeting a miserable end. In this life, she returned to before everything went wrong. She would not fight for false affection or beg for favor. She would take control of the household, protect the legitimate line, and purge the family from within. First, she would restore order as the eldest legitimate daughter in her birth family. Then, she would seize power as mistress of her husband's household. In the end, everyone who had climbed over her mother's blood and bones would pay back every last debt, with interest.
I still haven't figured it out yet, I don't know if it's the madam or the eldest lady.