Lin Yu, a grassroots worker involved in flood control and disaster relief, is swept away by the flood while saving two elderly people. When she opens her eyes, she finds herself in the body of Shen Yurong, the nearly fifty-year-old Old Madam of the Marquis of Yongning's household, who had just been pushed into the water. The original Shen Yurong spent her entire life being timid and weak, while Second Madam Liu gradually seized control of the household. But who is Lin Yu? A graduate with a degree in auditing, she is exceptionally skilled at checking accounts and cleaning up messes. Rather than crying upon awakening, she immediately takes up the account books and begins setting her trap, investigating the finances while making her plans. She helps her daughter-in-law, Madam Su, reclaim her legitimate eldest grandson's food allowance, assists her son Xiao Yanchen in resolving a political crisis at court, and gradually brings the Marquis's household back onto the right track.