Before this drama, my favourite all-time drama was Kill Me, Heal Me, but somehow this drama topped that one.

---STORY---
The story was AMAZING. Sooo many plot twists that actually make sense and contribute to the story, and there are 0 filler episodes. Every single SECOND of the drama was important and meaningful. I had no idea what I was getting myself into when I first started watching, but it turned out to be SO amazing. I cried so much throughout the drama, my eyes are like permanently puffy.

---ACTING/CAST---
I think we can all agree that EVERY single cast member was AMAZING. I first saw Moon Chae-won in Running Man, and BOYYY she is so talented. Lee joon-gi was really good in Scarlet Heart, but his acting in this drama was beyond amazing. He played both an unemotional, unfeeling psychopath, a loving dad and husband, and a crazed man. Kim Ji-hoon is new to me, but he was genuinely SO scary in the drama I nearly cried out of fear every time I saw him. That's how good he was. I loved Jang Hee-jin and Geo Hyun-woo as well (also new to me). Literally every secondary character no matter how small their role was really well casted and well done.

---MUSIC---
There were two distinct theme songs that I remember from this drama, but none left the same effect as Auditory Hallucination (KMHM). The creepy background music literally made me cry out of fear and it really made the scary moments so much scarier.

---OVERALL---
I can't even begin to explain how amazing this drama is. I seriously recommend you watch the first episode and you'l automatically be hooked. I would definitely rewatch this, 100 times over and never get sick of it. It's one of those.