All the cases are based on true events and criminals such as Yoo Young-chul, therefore the show has a more realistic storyline that doesn't waste time on useless sub plots, *cough* romance or politics *cough*, and really makes you sympathize for the victims. From the media press all the way down to the clothes they were wearing when they were arrested is accurate, although I would say the Red Hat Killer's case is more fictionalized from Lee Chun-jae. Please be reminded this is based off Profiler Kwon-il yong's novel from his real accounts of being South Korea's first profiler but just a bit more dramatised.

The drama has a serious cinematic tone but is enjoyable as it shifts between slow burn, to some episodes that are very fast paced and intense (especially starting from Episode 7) that had my jaw unhinged and heart racing. The narrative of the criminals are shown in between investigations so you can see them commit crimes which adds to the suspense. Although, keep in mind these criminals are not geniuses and they are humans who can be caught by studying their psychology and behaviour therefore the drama thickens even if they get caught. This was also quite a while ago and the police were different back then so you have to be open minded on how they operate with their limited resources, but even then they are the least annoying police force I have seen in a crime drama who have logical thinking and encourages their officers. Everything feels like it's meticulously set in the right time period and small references to notable past events such as 9/11 and the World Cup are made, similarly to "Reply 1988".

Ha-young is a quiet but straight forward man and even though he expresses very little, Kim Nam-gil is amazing at portraying nuanced emotions. His fellow friend and profiler, Young-soo, is such a lovable and optimistic character who supports Ha-young along with their young intern, Woo-joo, who is a bit clueless and cute. Both bring such a lightheartedness to this dark show and also display their cleverness.

Tae-goo, the one female detective also feels like an actual individual with her own real struggles and goals compared to many other females like her in crime dramas. Comedic relief is given from most of the main cast like Kim Won-hae and Lee Dae-yeon who are great fun supporting actors in crime dramas. The acting is superb from every single character, including the criminals. Everyone has great chemistry together and you can really tell how much the crimes affect the profilers and detectives who express human emotions all the while maintaining detached and objective as they solve crimes like the professionals they are.

The soundtrack is moody, haunting and soft that reflects the drama beautifully and captures the essence of it. Isaac Hong (well loved and known), The Nerd Connection (a hidden k-indie gem), Kim So-yeon (an ethereal angel) and 4MEN (triple threat with sweet contrasting voices) are the OST singers.

Overall, it's similar to the likes of "Mind Hunter" though much more prevalent to Korean history and culture. It displays how even though America was developing and using profiling methods at that time, the rest of the world was just grasping the idea of it. It's a brilliant production that's worth watching as you will be completely immersed. If you're having deja vu with these cases from seeing it in other dramas it's because these cases literally inspired so many criminal characters in thriller k-dramas.

Former FBI agent explains criminal profiling: https://youtu.be/LHqbfJ3tq4Y

Kim Nam-gil and Profiler Kwon Il-yong's QnA discussion on criminal profiling:
https://youtube.com/playlist?list=PLBD3KVgNp_ozVH5aEfw2-RlIy6G-1klYN