Although this was more of a mystery-thriller than a horror for me, nevertheless there was a time when I felt like there was someone watching me beyond a door at night while I was in the middle of watching this series. I loved the overall idea, the premise, the twist and the ending. I also liked that the police were involved as well, and there was a nice overlap of natural and supernatural. I could not stop clicking on the next episode, one after the other.
The only complain I have about the drama is the motive behind the actual spirit's hatred/resentment. That could have been more fleshed out. But overall, I really enjoyed this.