In Jiangnan, the prestigious Su family welcomes Shen Qingyi as its new daughter-in-law. Half a month after her marriage, her mother-in-law, Madam Lu, remains cold toward her, constantly finding fault with her embroidery and account books. From managing purchases and storerooms to handling clan gatherings, Madam Lu tests her at every turn. Gentle on the outside but strong-willed within, Shen Qingyi relies on her attentiveness and perseverance to resolve accounting discrepancies, ancestral ritual mistakes, and disputes over family property one by one. Her considerate and understanding husband, Su Yanzhou, supports her, while her loyal maid, Cuiping, stays by her side and Nanny Li watches from the sidelines. After enduring tests and gradually learning to understand each other, Qingyi wins her mother-in-law's approval through her sincerity. She slowly grows into the true mistress of the Su household, maintaining her dignity amid the strict rules of the inner residence and forging a path of her own.