Ok so I started this drama because of Jang Na Ra and Seo In Guk like most out there!! And let me tell you, I wasn't disappointed! The basic story: How people become monsters is awesome! Like really really cool concept so I loved it, a lot at that! I loved how the story started but it got kind of boring after eight or ninth episode? I kept waiting for the climax which never came and just like that it ended! The end was pretty speedy, I was super confused so I had to read different discussions of the viewers to know what actually happened though it wasn't that bad =D. Acting was SUPERB! We all know about Seo In Guk who was awesome in this but for me, someone else surpassed him in this drama and that was Park Bo Gum! Seriously, this guy rocked the show with his complex character and PERFECT expressions! Looking forward to his work in the future dramas! Its been so long since I actually felt what the character was feeling, for me he was that good! Jang Na Ra as usual was super sweet with her cheerful and somewhat dumb personality? But it was perfect for the story and I LOVED her =3 Other than these three main leads, lets not forget Team Leader =p and others! They were really good, the investigation team was love =3 Overall it was a good drama, I couldn't sit still until I finished it! Watched it like crazy! If you are a fan of crime-like dramas and root for bromance rather than romance than give it a shot!!