Ji Wanwan, a modern woman who loved extreme sports, dies in a bungee jumping accident and transmigrates into the body of a fifteen-year-old girl in the Great Jin Dynasty. The original host was known throughout the capital as the Ji family's fool, possessing the mental capacity of a young child. Upon waking, Ji Wanwan finds herself in a precarious situation after accidentally falling from the sky and landing on Rong Yu, the only son of the powerful Duke of Rong. Panicked and seeking escape, she is intercepted by a five-year-old boy named Shen Zhinan, who claims she is his mother. Despite her initial skepticism, Ji Wanwan accepts his help, and he guides her safely back to the Ji residence using his encyclopedic knowledge of the capital's alleyways.
At the Ji mansion, Ji Wanwan confronts her so-called best friend, Lin Yourou, who had orchestrated the bungee incident to make Ji Wanwan look foolish in front of Rong Yu. When Duke Rong's guards attempt to detain them, Shen Zhinan produces a Death-Exemption Golden Medal, a rare imperial token previously held only by the legendary Qin Wang and the Prime Minister, Shen Huaiji. The appearance of the medal halts the confrontation and forces the Duke's household to back down. Inside the residence, Ji Wanwan learns from Shen Zhinan that he is indeed her son from the future, born to her and Shen Huaiji, the cold and ruthless Prime Minister. He has traveled back in time to ensure his mother's happiness and to protect the family from future tragedies.
Ji Wanwan decides to keep Shen Zhinan's true identity secret, posing as his foolish cousin to avoid suspicion. Meanwhile, Shen Huaiji becomes intrigued by the appearance of Qin Wang's golden medal and the strange child, ordering his shadow guards to investigate Ji Wanwan and the boy. Ji Wanwan uses her modern knowledge and Shen Zhinan's foresight to navigate court politics and family drama. She exposes Lin Yourou's schemes at the Duke's mansion, earning the sympathy and protection of the Duchess of Rong. She also attempts to help her cold second brother, Ji Mingjing, who is destined to miss the Military Imperial Examination due to a misunderstanding with He Ying, the fierce granddaughter of General He.
Ji Wanwan and Shen Zhinan team up to distract He Ying, allowing Ji Mingjing to take his exam. In the process, Ji Wanwan leads He Ying into a maze of alleys where she gets lost and injures her ankle. Ji Mingjing, driven by a sense of duty, finds and carries her home, sparking an unexpected connection between the two. As Ji Wanwan adjusts to her new life, she must balance her desire for independence with the growing entanglement with Shen Huaiji, whose interest in her is piqued by her sudden change in behavior and the mysterious child who resembles him. The story follows her efforts to change her fate, protect her family, and navigate the complex political landscape of the capital while uncovering the secrets behind the golden medal and her future.
