Wonderful show. Espionage done right, a balance of style, grit and gore. Murky office politics, alliances that break and are reformed and just enough of the lone wolf, Nam Koong Min, stubbornly struggling to understand himself and to find the perfect mole. Very nice plays on the genre. Lots of fights. I like them but you may not. My favorite things: 3 fully characterized female colleagues sharing the screen time, none of them all good or all bad. NM, as a stoic muscular handsome beast, both puzzled and pugnacious.
My warning, requires as much intellectual fortitude as much shorter novels or movies but for 12 hours. You Must Take Breaks, or you risk breaking your mind. Eps 13-14 are a prequel set in the 20teens.