The modern plot lacks everything, intensity, pace, and chemistry between leads. The character of 21 century girl is inconsistent. She is supposed to be a brave hero, she is a fireman after all, but she is easily manipulated and walks around grumpy, and her decisions often don't make sense.
It would be a simple and average story about a ghost, revenge and a girl, but fortunately, we have a true love story in ancient Silla. I wish it would be a main plot!
It has a deep meaning of love and death, beautiful scenes and visuals.

It is hard to rationally justify the sins of the previous life and the endless punishment, and that's why the scenario can't be good, but it's enough for an uncomplicated drama.
The ending? Not bad.