This is a  very good drama.
Nam Goong Min, Yoo Joon Sang and Uhm Ji Wok did an amazing job. I loved the acting most.
The plot was interesting. There was a tiny slice of romance that gave the story some kind of sweetness.
There was something that made me feel like i'm watching super hero movie, but without the special effects and super powers.
I didn't enjoy only one moment in the ending -  but this is personal taste.

The OST is really good, sadly i couldn't find most memorable melody.