until episode 10 they built the tension but Very poor acting by both lead actors

Ending was total let down
You built everything for end and then nothing really happened
Director wasn't able to fit all that in 12 episodes
There were no believable emotion in whole show
until Episode 10 Lee hayrun was noticing tension between Cop couple but after 10 Director decide to make her stupid fangirl who already noticed cop couple but suddenly she is too deep in love with Ji chang Wook
ji chang wook shows no emotion for Miss Lee at all and she wasn't able to notice anything after episode 10
Junmo was free to kill and former cop they don't even was able to catch

Whole show was about catching drug gang boss but our Murderer Cop Ji Chang Wook let him go
he kill an innocent investigator,
But since his wife still love her criminal lover he let him run away what nonsense logic is that
that wife cheat on her husband with a criminal in front of him by using work as excuse
his boss himself look like a gang leader then police, Acting level of Ji Chang Wook in this show drop to -99 {negative}

At the end they are back normal walking in there home after his cop wife told him that she will always love that criminal guy and he is her compromise who she can't divorce or leave for a criminal because it will taint her Cop family
Junmo shot a man who was about to shot himself, in both situation other person died
but junmo wanted credit for his second murder and after that what is left of his marriage ?
Junmo killed his wife's first love she still love and cry for in front of her husband

I give 4/10 for those 10 episodes in which this drama was logical, but at the end just throw the logic out

It was first time i see ji chang wook being this Lazy in his acting,
K2 was better and Empress Ki was the best of Ji chang Wook after that its all went downhill in his acting and choice of scripts.