Just finished watched this Masterpiece drama last month. Watching this just because of Kim Nam Gil. Love all the stories for each of the killers. They had their own motive for all the cruel murders. Most of them had terrible & dark past. And I really love the Criminal Behavioral Analysis team. Kim Nam Gil & Jin Seon Kyu chemistry is so perfect. The way they interview all the psycho killers and make a research about their past (background) is so amazing. Each of the killers are so damn psycho and crazy. Thumbs up to all of the actors that played as a psycho killers. Although all of them are new face (actor) but damn their acting is really another level. I can feel all the emotions. So sad its only 12 EP, I wish there's more EP for this drama. Hope to see season 2.