The best part of this show was probably in the first half when Lee Joon-gi's character, Do Hyun-so was playing cat and mouse chess with everyone including Moon Chae-won's Ji-won. It was both edge of the seat stuff and Hitchcock-like. Even if he wasn't actually guilty of much by way of crime, he did perpetuate a degree of deception against his own family. Because of that, the resolution that we got, made some measure of sense. Not in terms of plausibility... all of that went out of the window in the final act with the heavy makjang emphasis... but in terms of his journey as a man who was sinned against much more than he sinned. Whatever his natural propensities were, they were muted by his relationship to Ji-won, the girl who pursued him and married him. Her belief in him and the fundamental good in him was what, according to the show, saved him mind, body and soul. Love... so the saying goes... conquers all. To avoid an outright happily-ever-after (which is what they were really aiming at here), they compromised and gave us the amnesia trope on a platter -- a symbolic cleansing and reset.
While that might be aimed to give viewers the warm fuzzies, it's the safe option for the show to take. Ji-won stood by her man even when he "forgot her" and it paid dividends. More than that she proved to the world that there was sufficient good in him to transcend genetics and all the odds stacked against him in terms of upbringing and societal marginalization. Amnesia also meant that Do Hyun-so would do his sackcloth and ashes routine, self-reflecting and a bit of self-flagellation on top of all that.
Before her departure Hae-su offers a pep talk. They can't spend all their time wondering around the wilderness second-guessing themselves. Life has to be lived and there are people around who care. Don't look a gift horse in the mouth. More importantly, they shouldn't live under the shadow of their father's dark legacy.
Clearly at the heart of this, is a drama about marriage and family. I think the final arc is proof of that. It is also why the show doesn't much rise above its early claims to be a serious police procedural. It's a contest of nature vs nurture on some level but the show doesn't go deep into anything because ultimately it's a family drama with the window dressing of psychothriller, crime show. It is first and foremost a love story. That's the double-edged sword. Contrary to the title, the show wasn't going the whole hog to turn Do Hyun-so into the image of his father.
Hyun-so taking on Hee-saeng's identity while the latter was in a coma was highly symbolic on hindsight. The latter was the apprentice Do Min-seok had groomed. While Hee-saeng had the bloodlust, he didn't have the mental acuity of his mentor. He survived under the veneer of respectability which his wealthy upper middle class professional parents gave. It seems that they knew very early on what his tendencies were but were hapless in nipping the matter in the bud. As Hyun-soo's alter ego and nemesis the question inevitably arises. So is it nature or nurture? The Baeks were quick to blame Do Min-seok's diabolical influence to diminish their own culpability. The school incident when he dropped the brick on someone from the roof was at the very least a hint of an ASPD nature. But ASPD doesn't have to be a death sentence. Or be followed by murderous behaviours.
It is suggestive that Baek Man-woo even in his interactions with Hyun-so in the early days demonstrates malevolent tendencies. Hiding his comatosed son in a secret room behind the closet to maintain his professional standing seems to me highly dubious. Doing deals with Hyun-so to take on Hee-saeng's identity shows a pattern of behaviour. Advising Hyun-so to bump off obstacles along the way without batting an eyelash is indicative. While he doesn't go around killing random victims, he is not above engaging in morally questionable acts. The elephant in this room is the question of whether Do Min-seok was really the primary insidious influence on Hee-saeng's life because his birth father had serious character flaws which he could have picked up on growing up in that household.
Sadly the exploration of evil within families though a fascinating topic doesn't really get much of a probe beyond the usual platitudes. This also I think compromised the quality of the detective work towards the end... the silliness... all in service of the inevitable but needless melodramatic climax. Even though on first appearances the show looked like it was breaking the mould, it turned out more like a revenge story culminating in a big showdown between antihero and villain. This villain is not so terrifying as he is sheltered by wealth.
The part about Ji-won that was interesting is her much touted evidence-based approach to life. To some it seems initially to be something of a weakness to be exploited but as the story progresses, it becomes the quality (arguably an asset) that keeps their marriage together. Hyun-so saw himself as an imposter who acted in ways that would be socially acceptable as a husband and father but what Ji-won saw was beyond the social niceties. Effectively it wasn't all an act. There was a lot more to Hyun-so than even he himself realised or claimed to be Until his sister observed that he had changed, he was unaware that he was more than a programmed automaton... the absolute husband as it were. There's a certain charm to Hyun-so's honesty and Ji-won's faith in what was evident in his expressions of affection to her and Eun-ha. His claims and her own experiences were in contest and in the end, it was her experience that overruled everything. I think his do or die attempts to protect what he had as Baek Hee-saeng was partial proof to her that he was being driven more than just cold calculation in maintaining appearances.
As far as the acting is concerned, it's a veteran cast with little to criticize. Lee Joon-gi was terrific as one would expect and Moon Chae-won did very well with an emotional rollercoaster journey. I was delighted to see Kim Ji-hoon playing against type and it seemed that he did it with no small amount of relish. While I was entertained for the most part and was even moved by certain interactions, I don't think it's a show I would revisit any time soon.