There is originality to this series that is mesmerizing. The storyline is gripping, emotional, exciting and mysterious - all at once. The male actors have also done an outstanding job and their emotions are worn on their sleeves masterfully. That said, it is not perfect. The female lead with her childish and immature behaviour is frequently annoying. However, what is most difficult to digest is why there was a need to bride-match a high schooler who behaves like a 12-year-old with a man who is in his mid-30s and has lived for over 900 years. It is this dichotomy that somehow really becomes and stays a thorn in the viewing side. Comments could be made regarding the skillfulness of the main actress, but perhaps this is fully a matter of personal opinion. And then there is the matter of the ending - what a letdown. To get our hopes up only to be so brutally disappointed in a manner that made little to no sense - it was a true storyline letdown. It is still a pleasurable must-watch for lovers of Korean series.