A thousand years ago, in the battle between immortals and demons, the demon king "Baize" was defeated, and his body was destroyed but his spirit was not destroyed. After a thousand years, the demon king's spirit, sealed in the fragments of the Qingluan Mirror, was about to awaken. In order to protect the world, the disciple of the immortal realm, Mu Qing, went to the demon realm half a step further to search for the fragments of the Qingluan Mirror. As soon as Mu Qing arrived at Banbuduo, where humans and demons coexist, he met the cat demon Chao Yan. She wholeheartedly helped Mu Qing find the fragments of Qingluan Mirror, and the two of them embarked on an adventure together. During the process, Mu Qing and Chao Yan secretly developed feelings, and Mu Qing gradually let go of their immortal and demon grudges. However, they found that their relationship was not only that but also a premeditation that had been planned for thousands of years.