I was skeptical of this drama at first because I thought it was going to be unnecessarily complicated and boring. Instead I got a one of a kind, unique drama that instantly shot up to my favorite drama of all time. It even beat out the recently finished Goblin--which I absolutely loved. Everything about this drama was perfection. The acting, the leads, the plot everything. The plot--while having a lot of twists and turns--never got overly complicated where I could no longer understand it. The writers did an excellent job explaining everything. It never dragged. Which I worried about after episode 7 but something was always happening to keep viewers on their toes. This was the most suspenseful and thrilling kdrama plot I've ever seen. The romance never slowed down the pacing, either. There was just the right amount, which I was so thankful for. The romance was written well too. No miscommunication between the leads, no hidden truths, no repetitive angst between them, and the leading man was never rude or downright mean to the lead girl like so many other dramas. Lee Jung Suk has quickly become an all time favorite actor of mine. This was my first drama of his and I want to now go and watch his other dramas. He was so perfect as Kang Cheol. I loved him to pieces. Oh Yeon Joo was a great female lead who actually thinks and has common sense. The ending was really fitting and thankfully a happy one--if a little bittersweet. I loved the ost as well. Hardly ever do I fall in love with an entire ost from a drama, but this one I did. Especially the main ending song. Oh my God, I love that song to death. I would recommend this drama to anyone. It literally has everything and you will definitely not be bored. There's no middle sag, just non stop on the edge of your seat plot twists.