I absolutely adore this drama and without a doubt is within my top ten favourite asian dramas. Follows probably the most beautiful love story I've ever seen (ofcourse w some bomb CGI).
Rewatched and completed this drama for the third time, learning more and more about the ending every time I watch it. I must say, after 61 episodes you really weren't watching it to have the female lead die in the end *cries in 50 different languages* until they finally reunite in the last 15 minutes of the show :')
It does take some understanding to know what's going on at the end as it is unclear (which I believe is the directors intention, sucks for us). If anything, read the book as a source to help you understand and brace ourself for an expected season 2!
If you're planning on watching it, I promise the 63 - hour long - episodes are entirely worth it and it is an amazing drama that deserves all of its hype!