The great herbalist Mo Tianquan (starring Richard NG) has a daughter who had been suffering from incurable disease since little and could not get through her twentieth year. To save her life, Mo spent his life working on the Elixir. Unfortunately, there was one missing ingredient of The Life-sustaining Flower. Teacher Mo had to take the long shot to maintain his daughter life. Now Xin was saved, while her body failed to create blood. She then was turned into a monster needed to suck human blood regularly, and resulted in remained beauty. 20 years later, Herbalist Li (starring CHIN Siu Ho) comes back and finds out Teacher Mo hided all the truth for making Xin live her “normal life” and he even pretended to be the blood-sucking monster. Looking at his former love becoming a blood-sucking monster every full moon night, he feels hopeless. The Elixir keeps Xin alive and young forever, but it also makes her suffer as a zombie. If the herbalist could find the last ingredient for the Elixir? If Elixir really exists in the world just as there is no immortality?