Yan Dan is the sole descendant of the ancient tribe the Four-Leaved Scorpion. Yan Dan's entire being is a treasure trove of medicines. She and twin sister Zhi Xi transformed into human form a century before while attending the Queen Mother's Feast, but Yan Dan faced the greatest trial of her life - the love trial. Falling in love with Lord Ying Yuan resulted in her wasting the following 800 years forgetting him. Such a high price to pay!