I started this drama because the story seemed interesting and finished it in a couple of days which is a miracle for me. The most important thing is there were almost no "plot conveniences". It was gripping till the last episode. Even if you can guess the murderer, you'll wonder about the main leads' choices and where it will take them. Main leads' chemistry didn't strike me as amazing at first. The more I got to know about Do Hyun Su the more I could understand how Cha Ji Won come to love him. It mainly revolves around them so, don't expect much from side characters. What more I would have loved to see? Baek He Song - Do Min Seok relationship of course. But I gues it would have too much flashbacks then so that's ok.
I loved, loved, loved the ending. Writer made an amazing point by letting Cha Ji won respect Hyun Su's decision. Well written, well played and definitely very touching.
And...Isn't that OST great?
https://www.youtube.com/watch?v=_cvxjZkbhyI