Modern corporate slave Xu Wan transmigrates into the legitimate daughter of the Minister's Mansion and marries into the Marquis Mansion. Hoping to enjoy a life of leisure, she instead takes on the heavy responsibility of educating the eight-year-old "little demon king" Zong Jincheng for generous rewards. Facing her unruly stepson, she uses modern educational thinking to match wits and courage, and has the diligent and gentle Zong Wenxiu accompany his younger brother in his studies. Through the chaotic daily life, the three of them establish family affection, and Zong Jincheng transforms from an anti-learning playboy into a motivated youth. However, the mysteries of the Marquis Mansion's background and conflicts with powerful nobles follow one after another, and Zong Zhao, who has been missing for many years, also appears at a critical moment.