The story line is lacking, action is average, not as cool as dramas starring Ji Chang Wook, and is repetitive. The only reason why I didn't stop watching was because NANA is gorgeous and Jang Ki Yong is awesome. The other supporting actors are so-so and didn’t stand out to me much. Okay, maybe Philip (Lee Jae Won) stood out but I’m so used to him from Man from No Where and he fit this role well. It is difficult to give this anything higher than 7 and I’m giving a generous 6.5. There are simply much better action dramas than this and I know OCN has a list as well based on viewer ratings. I would say just watch this if you are into the actors and don’t mind a lot of plot holes. The relationship tree between all the casts had me confused and no clear explanation was given and left to our imagination.