I watched ep 5 last night.it is wow. The mystery is revealed one by one starting from ep 5. So MKT is already know that KMY is the girl from his past.
I read some comments and i have some guesses.
1. The female patient who wants to introduce her daughter to MKT is KMY stepmother.
2. The sound of lady searching for help is her stepmother voice
3. Her father is the bluebeard
4. Death of MKT's mother is related to death of KMY's biological mother.
5. Lady in black dress who wanders in hospital is not ghost.
I have a plot in my mind but i will not write it. Not fun.
I hope this drama has a happy ending for everyone. Except for that reporter who blackmails KMY and her boss. I hope, somehow that guy ends up in prison. That guy is a true evil