Tldr; 12 eps was perfect for this plotline. I think the ending was a perfect ending to the situation and the acting from everyone was phenomenal. OST.. can't even remember the music lol

The drama starts off with JM, an underdog cop who can't get higher than his desk cop rank. He married into a renowned cop family where everyone is basically a high ranking cop - even his wife. You can see that the marriage is already stained from ep 1 because his in-laws constantly shits on him about his rank in the police world and no matter how many sweet words his wife can whisper into his ears, the wound is too deep. (You know what they say about men who feel inferior).

JM gets proposed by one of his cop sunbae and friend to go undercover and infiltrate KC's gang so they can take down the drug trafficking triad. He only accepts with the condition of getting promoted (see how deep his wound is? and how desperately he wants to prove that he's worthy to his wife & in-laws?)

He joins under a alias and this is the beginning of JM's downfall. At the beginning, he tries his best to stick to his morals and his duty as a copy, but if everyone in the gang keeps suspecting you... it's kind of hard to be all bark and no bite ESP in a gang where they kill. His wife, EJ finds out that he went undercover and ofc.. his wife is KC's first love. Obviously with this known, even if she didn't want to participate in the investigation, she HAS to be part of it bc KC knows her.

I know this adds to the plot.. but let's talk about EJ. Her character was bland to me. I don't hate the actress but her character gave nothing but a headache to the plotline. I guess we can say that JM really turned into someone who didn't want to be in order to protect her but she really just put herself back into the situation of always being there even when it wasn't needed. Sure her first move was helpful to JM to get deeper into the gang and to gain KC's trust... but grass is always greener on the other side.

The love triangle begins and this was when I got annoyed of the drama. Here's an example of how the industry not knowing how to write strong FL. After the 3rd... 4th... 5th time EJ met up with KC for NO GOOD REASON, was when you can tell that she was masking her feelings by trying to convince herself that she was only doing this for her husband.

YES, both JM and EJ cheated and their marriage was doomed from the start. I will say... EJ really caught feelings and JM just felt bad for HR like he did for KC. He was able to relate to the both of them bc of his own fucked up past. If he really like HR is one thing, but I know (& the audience can see) that he was conflicted and confused with his actions towards HR. I want to say he's been undercover for so long and him and EJ weren't able to communicate, he was weak. But he still cheated.

The down fall of the gang was not bc KC got involved with EJ again. It was bc he got emotional about Taeho. His inner circle kept telling him how sus how everything was happening since JM joined the gang and he didn't listen. Sure he did a mere background check, but as someone who is the big boss of his gang.. he really done goofed in believing people when he should know that documents can be forged.

The brotherhood of the drama was strong until it wasn't. There's always a power struggle and jealousy and betrayal - this is why you can't get emotional about the past and just let people walk away after betraying you.

My take on the last 20 mins of ep 12. JM felt an emotional bond to KC no matter how much he wants to deny it. That's why he gave him the opportunity to escape and actually live the good life he wanted/dreamt of. But KC's (lk) obsession over EJ was his downfall. When the 3 of them were in the couple's house, you can already see the dynamic has shifted. EJ couldn't see JM the same anymore, JM couldn't forget everything that he has done and what has happened when he was undercover, and KC.... he was too wrapped up in trying to figure out if EJ really loved him to understand the great opportunity JM gave him.
I find the talk between a mafia boss and a cop about being sinners funny. After all he has done, he talks about being a sinner but blames EJ about being a sinner for mm.. essentially doing her job. & EJ talking about how she will repent for the rest of her life for... ONCE AGAIN, doing her duty as a cop. IDC if he was your first love, he's a mafia boss who kills and is importing drugs into your country. To think, someone who grew up in a cop family, she'd have a stronger mindset. But back to the point... I believe that JM shot KC when he was about to unalive himself was bc it was his last attempt to show his wife that he loves her. I know.. that sounds weird bc he just SHOT someone in front of her BUT my point is, he knew that if KC unalived himself in front of them, EJ will blame herself for the rest of her life. If JM shot him, she will have him to blame. Their marriage ending was a good choice.

The ending was great for the situation. I personally don't think there needs to be a season 2 (if there even is one) bc season 2 will have a new plotline and probably a new cast. They've exhausted every character they could in this season.

Oh and one last thing... considering how this is BIBI's first real role. She DELIVERED. I loved her character more than EJ. The chemistry between BIBI and JCW was 100000/10.