Everything a kdrama/series should have.
Production, acting, story, script, plot twist, OST, everything at its best!
It's my number one favorite so far.
Highly recommended.
The camera shots are insanely good and the action sequences are the best I've seen.
I've seen a few kdramas over the past 13 years, each one with its own genre, obviously and this one has exceed everything, not only in the kdrama category, but series in general.
I'm usually very critical, but this one owns my heart.
Also, my favorite genre is mafia and this one was the only that kept me interested from the very beginning till the end.