The past is as long as the mountains separated by mountains, everything starts over and over again.
The good life of the old demon who has lived for 3999 years has come to an end. As the demon king, he is suddenly told that he can only live for one more year? The only way to survive is to give up all his cultivation and condescend to become the disciple of the Taoist priest he hates most.
But is it really that simple?
The truth about the war between humans and demons a hundred years ago is like the secret between immortals and demons separated by the mist.
Pei Sheng, who has always been aloof, must take on the responsibility of the Demon King after losing his cultivation and restore the truth behind the facts.
An ancient fairy tale, a love-hate story about a thousand-year-old demon king who is obsessed with face and a tough-tongued man, and the girl who is the sole leader of a sect who is cold on the outside but warm on the inside.