This is one of the best dramas I've ever seen in that it truly accomplishes what it set out to do. It's disturbing, thought-provoking, incredibly intense and the most gripping drama I've probably ever seen. There are plenty of other shows I've seen where I'm invested in the characters and want to make sure nothing happens to them, but there are none where I've felt the level of visceral fear for the lead as I did in this show. Sometimes it was so painful or engrossing that it was almost painful.
This drama is dark and scary so it may not be for everyone, but it is an excellent drama. Highly recommend.