I honestly thought this drama was a mess at first glance but by the second or third episode I realized how wrong I was. This drama is painstakingly constructed and carefully planned; every loose end, question and mystery is left for you to ponder until the right moment. I highly enjoyed this story because it was never dull and did not leave me wanting more. Each time a mystery gains a new detail or is solved completely something new develops to keep you engaged and the chemistry and depth of the characters was absolutely amazing. I also enjoyed the use of multiple themes in the show which gave plenty of elements and moments to keep it from getting stale. This show has supernatural elements, comedy, romance, and crime - suitable for many viewers. Song Seung Heon was great. I cannot be happier with his performance. He portrayed Moo Gang and Black so well, even matching his acting with Kim Tae Woo, making the personality seamless no matter the scene. That being said the show stealer for me was Kim Won Hae. I have yet to see the man do a poor job with any character he is given and this role was no different. My only complaint with the cast was Go Ah Ra. There was something lacking in her portrayal of Ha Ram that nagged me off and on while watching and I realized I did not like how inconsistent her strength was. She is potentially a very strong female character but she never stays strong, crying and focusing on things that are not very important in the big picture. I took it as the writer giving her more room for growth and development, a chance to learn more about herself, but it at times made her come off as immature not someone who lacks trust and is forced to be self reliant.  However, with the story and the outstanding performances by the rest of the cast I was able to overlook it for the most part. The music for this show and the transitions/cut scenes were wonderfully placed. There was never a jagged moment that interrupted the viewing experience. The songs, both with lyrics and instrumental, were very nice and I may try to find some of them. The episodes are slightly longer at times than other shows but with how well they are executed I did not mind. This show is so good it is possible to rewatch, even more than once, but it is not a show you can really pick an episode and just jump into. As far as I'm concerned the show is so good I wouldn't want to just jump in randomly, I would invest the time to rewatch it fully. This show is also binge worthy af for any of my marathon friends.
Overall, this is one of the best show of 2017 for me. I hope this helps and happy drama watching!!  :)