Lin Yaoyao accidentally travels to a world of immortal cultivation and becomes a cauldron disciple, immediately finding herself hunted down. At the critical moment, she activates the Demon King System and obtains all sorts of bizarre abilities. However, she gradually discovers that she is actually the sealed Demon King herself, Yu Yao. At Fuyu Palace, she navigates the complicated relationship between Mo Ran, her aloof master, and Xing Yuan, the seductive and sinister Demon King, while concealing her identity and searching for a way back to the real world. As her memories awaken, she must confront the conflict between immortals and demons, a fate entangled with love and hatred, and make a new choice about her own path.