Yan Dan is the only descendant of an ancient tribe, the four-leaf scorpion. Since ancient times, her whole body is a treasure of medicine. She and her twin sister Zhi Xi were able to cultivate into human form at the Queen Mother's Feast a hundred years in advance, and encountered the biggest trial in her life - the love trial. She fell in love with Lord Ying Yuan but had to spend the next eight hundred years forgetting him. However at this time, Yu Mo suddenly entered her life, and become her great support. Everyday, Yu Mo takes Yan Dan out to do good deeds. One day while they were punishing evil, they meet Lord Ying Yuan's current reincarnation, Tang Zhou, who is currently a demon hunter. They help Tang Zhou search for the four ancient artifacts, and also discover a mysterious secret.