I'd like to begin with a pet peeve I have about the drama: Product Placements were annoying and obvious. Movies and TV shows in the US rarely use product placement, and if they do, it's notable and not woven into the dialogue; perhaps this is why I noticed them. Complain over.

Having just finished The Fiery Priest (I'm still laughing...I loved it so much), I was eager to watch another drama with Kim Nan Gil. The actor has range because his character in Through the Darkness is nearly opposite to his character in FP. Still, the supporting cast's roles where well-drawn and execute so that the change in mindset that occurs over time in the series can be seen as genuine and not forced by a story line.

Pacing was excellent. Not interminable episodes of flashbacks, backstory, or lingering over a case for too many episodes. The result is a story that is presented over time, giving the viewer the opportunity to see the development of the Behavioral Analysis approaches and methods.

So, if you like a police series that looks at how the Behavioral Analysis unit got its start, and don't want to devote months of your life getting through it, then I recommend this for 1) bingeability 2) an interesting story but won't make you feel lost trying to figure out who did it.