Across the four seas and eight wastelands, the Nine-Tailed Fox clan of Qingqiu is held in the highest esteem. Twin sisters Bai Susu and Chi Li share the same lineage, yet their fates are worlds apart. The elder sister, Bai Susu, was born with nine tails, possesses a noble destiny, ascended to the throne as the Empress of Qingqiu, and rules a divine domain. The younger sister, Chi Li, though identical in appearance, was born with only eight tails and holds the status of a common noble. Since childhood, she lived under Bai Susu’s shadow, her heart filled with jealousy and resentment, leading her to have an affair with the most favored, fallen human prince in Bai Susu’s harem, with whom she conceived a child.
Everyone believed that Bai Susu, as Empress, had given birth to a nine-tailed pure-blooded heir with the fallen human prince—an heir destined for Qingqiu, celebrated by the entire nation. Chi Li, emulating this and having previously slept with the same prince, gave birth to an ordinary girl with no celestial aura, neither human nor demon.
Years of long-held jealousy and resentment completely twisted Chi Li’s heart. Taking advantage of Bai Susu’s postpartum weakness and relaxed palace security, she conspired with the human prince to swap the infants, surreptitiously replacing her sister's pure-blooded imperial heir with her own mixed-blood offspring. All of this was witnessed by Bai Susu, who remained outwardly composed.
For 500 years, Chi Li often cursed and beat her own daughter (Chi Xiaogou) in front of Bai Susu, venting her frustrations to spite her sister. Chi Xiaogou grew up full of malice under Chi Li’s abuse, while Bai Susu watched coldly, continuing to show affection to her own daughter (Bai Runyu). Under Bai Susu’s guidance, Bai Runyu increasingly displayed the traits of a future successor.
The truth was unveiled during the selection of the Heavenly Consort at the Heavenly Ladder: the child Chi Li wantonly abused and gave a vulgar name was her own biological daughter, while the one Bai Susu meticulously educated was her own. That night when Chi Li swapped the babies, Bai Susu had simply played along to trap her and eventually set things right.
