One of the best Korean psychological crime dramas with thought out / well researched scripts covering across a spectrum of human behaviours, personality traits, childhood trauma, familial and societal norms and judgements, work burnout, work demands etc. Great acting by respective actors in the role they portrayed from detectives, profilers and criminals. So realistic and thought provoking. This drama has gory moments. Not for the faint-hearted (I had to fast forward - or got my partner to do so while I shut my eyes). Subtitles were well scripted and on time (unlike some others). Well done!