Chu Feng was an Assassin. When he was on a mission, he failed and was hunted to a corner, so he jumped down a cliff. After his death, he entered the underworld. He spent 500 years and became the most powerful in the underworld. He became the most powerful demon called Demon King. 500 years in the underworld, his only desire is to return to earth and meet his lover, and manages to destroy the pearl of death in order to return to earth. But on earth, it turns out that there is a little girl who has been waiting for him...