After so many recommendations I finally bit the bullet and marathon-ed through this drama. And to put bluntly, this drama did not disappoint but instead exceeded my expectations. Usually, I find most Korean dramas to be draggy and slow but this drama really pulled me in. I could scarcely believe it when I got 20 episodes and wanted more. From the same writer who also wrote the popular time travel drama, Queen In Hyun's Man, I really applaud him for utilizing the time travel trope so well. This drama has to be the few dramas if not the first in my opinion that utilizes the idea of time travel so realistically and brilliantly. I walked in expected that I've seen everything with time travel, but this drama kept me on the edge of my seat until the very end. I also applaud the writer for writing such realistic, intelligent characters. Most kdramas concentrate on main characters leaving side characters one dimensional and often times, dim-witted. In this drama, each character has his/her own motivations, are consistent in their actions, and just overall believable. I'm also glad that writer wrote with the mind that the audience are not stupid and instead actively engages the audience's mind, curiosity, and imagination. Overall, I really enjoyed watching this drama for its intelligent plot and engaging characters. I would recommend marathoning at least the first four episodes of the drama though since the first few episodes are slow paced as the writer tries to paint the storyline to the audience. Once you got over the first few episodes, buckle your seats because I guarantee you you're going to embark on an awesome ride.