I really don't understand why this drama is so underrated.
Story:
I usually hate reincarnation stories because it takes them a lifetime to know that both of them are alive, but it wasn't a case for this one. The storyline and mystery was great, they could have added more suspense. Ending was great too. Wasn't too boring and Thriller and Romance were properly balanced.

Acting and Cast
Park Bo Young, Han So Hee and Ah Hyeon Seop perfect cast and perfect acting. I just felt like the ML's mother character was annoying and useless.

Music:
Into the abyss, my favorite OST amd also loved 'Starlight is Falling' like a meme song in between.

Overall, backstory and reincarnation story was great, didn't drag everything too much. This deserves more recognition.