It's not actually a drama. It is classified as "TV movie", and it really is one. Truthfully, I really like series produced by Korean cable broadcasts (like CGV, tvN, E-Channel). They are more mature, brave, and not typical. Probably my first contact with such drama was Joseon X Files (yes, you have the good connotations - it is all about THEM, only better tied up, without 13th season and main actor having more than one facial expression), and I loved it from the first episode. Shot not in a typical clean-angle way, sometimes from hand, shaky, delirious and oneiric (see, my demoniac possession... I mean, demonology research pays off), captured my attention from the very start. And it broke my brain at the end. I rewatched that last week, and it still had a great impression on me.
Anyway, this is not going to be huge post with my usual blabbering (oh, I love to write, whether it makes sense or not), but just presenting what I watch, and if it's to your liking - you may try it as well.