If you asked me for a crime-based/thriller drama with romance on the side; this is easily one of the few I would immediately suggest! Story The plot is fairly simple; a genius criminal profiler teams up with a female badass cop in order to solve crimes together. The story is somewhat common so when I first picked up this drama, I wasn't expecting too much since I've seen quite a few crime-based drama which did not exceed my expectations. Why? Because I am a huge fan of crime-based series. This drama started off with a Sherlock vibe and a mystery which was to be expected- hooking me right away. This story really makes us wonder, How do we define monsters in our society and whether are monsters born that way or did our society create them. The plotline was suspenseful as the mysteries from their past are brought up which leads to a web of more mysteries. Although this drama didn't have too much violence shown compared to other series, the one thing that stood out the most to me was the fact that this drama incorporated a psychological like aspect to it, as it makes you question society's morals and views on 'monsters'. The drama was paced well without any boring parts or major plotholes; however I would say that the ending could be improved on since it didn't give me a huge sense of closure. Acting The acting in this drama was superb; how Seo In Guk managed to convey his pain and emotions so easily made me fall in love with his character. The kid actors in this drama deserve an award as well since they portrayed their sadness and agony so well that it made me cry for them and their situation. Jang Na Ra who played the female lead was amazing; I've seen her in several other dramas and she always had the same soft easy-going character, so when I saw that her role in this was completely different- I was excited! She portrayed her character amazingly as I loved how she was able to stand up for herself! Her chemistry with In Guk was amazing as well! Although she is older than him by a few years, I think their chemistry together was really cute! Another actor I want to mention is Park Bo Gum (Jung Seon Ho). His acting and portrayal of a 'monster' character was beautifully done as it really makes you wonder and realize that 'monsters' or psychopaths you would call them really do not understand their actions. Music The music was really enjoyable; as it reminds you easily of a Sherlock vibe. It really gave you a mysterious detective kind of feeling and the other soundtracks were equally enjoyable! Rewatch This deserves a rewatch! Especially when you are able to rewatch it, you might be able to pick up on new details you may have missed before!