It is a debate which has puzzled, confused and bemused psychologists, philosophists and ethicists for centuries; is it our environment or innate what make us tick as human beings ?Why is it two children raised in different environments and circumstances end up as criminals?

Suspenseful as it is thought-provoking, screenwriter Kwon Ki Young ( Suspicious Partner,Protect the Boss) helps to bring this question to life through the focus us upon selective amnesic and genius criminal profiler Lee Hyun ( Seo-In guk). A sudden return back to South-Korea after years studying in the United States, opens up new wounds when he meets Detective Cha Ji-an ( Jang Na-Ra) in search also of the missing, calculative psychopath Lee Joon Young who both took something precious from them in their pasts. In addition to uncovering this old case again ,mysterious prosecutor Jung Sun Ho ( Park Bo-Min) 's sudden involvement in Lee Hyun's case will uncover some dark truths that perhaps would have been better left uncovered...

With a surprising cameo of D.O. as the younger Joon Young (our surprisingly captivating psychopathic killer), there's little to actually fault about our main cast's delivered performances .Jang Na-Ra and Seo-In Guk were brilliant within captivating the humanity and angst of our individual characters and undeniably Park Bo-gum was captivating within his role as the calculative and mysterious prosecutor with a dark past.

The majority of the drama centralises upon the intriguing cat and mouse games between Lee Hyun and our killer with surprising twists and turns along the way. However, the oddest and probably most out-of-place subgenre within the show of thrilling mind games and traumatic pasts, has to be the romantic element of the show evidently between Cha Ji-an and Lee Hyun. Whilst it did attempt to relieve these more ''noir'' elements by adding the light-hearted edge of romance, the pairing between the characters soon became a little over-centralised in the show. This didn't necessarily take away from the intrigue, but it lessened the impact of the events in particular of the more suspenseful elements of the drama as well as Ji-an's past for viewers. In addition to this, there were some notable plot inconsistencies around procedures and in particular the slightly ambiguous ending . ( It is difficult to say whether this was merely an intelligent attempt relieve Lee Hyun's trauma, or just simply lazy story-writing .)

Overall whilst Hello Monster was flawed by its questionable pairing choices, some inconsistencies and ending, the drama was certainly an intriguing and captivating suspense story with a decent story premise, intriguing characters as well as good performances from our cast. Certainly worth a watch if you are looking for a suspense story with more ethical questions, in particular the belief of ''nature and nurture'' and what makes us human.