With all of the positive and highly-rated reviews, I came in to burst the the beautiful the happy bubble. I simply didn't like this drama like most of the viewers.

Expectations? They are always high up there for me. To be frank, I only watched and finished watching this simply because two of my favorite actors - Seo In Guk and Park Go Bum, they are the main characters in this. The other cast - not so much, I was never a fan of Jang Na Ra's acting. Since this is mainly a psychological thriller with a bit of romance scenes, I now get why I didn't enjoy this as much. However, I do love an amazing mystery thriller, but this drama was lacking. Lacking what exactly? I wanted something crazy to drop out of the blue for me to watch it seriously. Like a deabak plot twist or something. Literally, I developed an attention span of a spoon while watching this. The only attention-worthy episodes were the first and the last ones. In reality, the plot line is detailed, written by a creative author, but the story wasn't fully developed and brought to life in my opinion. Good music is always a staple in a drama. I quite enjoyed the OST of Hello Monster, some songs are very catchy indeed.

So if I had to draw a quick conclusion, this drama could've been a lot more enjoyable and better, however, it lacked a lot. Myself, I don't even know exactly what it lacked, but it sure wasn't very entertaining and I almost dropped it. There are definitely a bunch of similar Kdramas that are better than this one out there so keep on looking!