This drama is quite different from Tsukasa Hojo's City Hunter, so do not wait for the lecherous Ryo Saeba :P... I adore the seriousness of it and the actors are amazing... from the charismatic Lee Yoon Sung, the strong-willed Kim Nana...the amazing Kim Young Joo ♥ to the main antagonist! This drama will make you cry, boil with anger and is one with a suspense to keep you on edge.
Even if the investigation and special effects lack a bit of professionalism, this drama is my favorite so far.. it is far from the boring, common, predictable k-drama.
I can't think of anyone giving a negative review for this drama... so watch it and you will not regret your 20 hours spent on it ;)