Chu Xunge, a powerful survivor from the apocalypse, transmigrates into the body of the neglected eldest princess of the Great Qian Kingdom and becomes bound to a system tasked with reforming a future tyrant. To extend her lifespan, she must lower the corruption level of Pei Xingzhi, a hostage prince who appears weak and harmless but is destined to plunge the dynasty into chaos. Chu Xunge protects him at every turn, giving him medicine to heal his wounds and even risking her life to shield him from arrows. Their bond deepens through a mysterious parasitic poison. Meanwhile, the Crown Prince and the Second Princess repeatedly frame them, throwing the imperial court into turmoil. Seeking to restore his kingdom, Pei Xingzhi pretends to ally himself with their enemies, creating misunderstandings, but ultimately risks his life to protect her when danger strikes. Chu Xunge accompanies him in suppressing the internal rebellion in the Kingdom of Yue, finally bringing his corruption level down to zero. She leads her troops to quell a palace coup and ascends the throne as Empress. Three years later, Pei Xingzhi arrives at the imperial capital with the entire territory of Yue as his wedding gift, accompanied by a magnificent bridal procession stretching ten miles, to reunite with her and spend their lives together.