I am just hoping that the first episode is not a dream, and they don't pull something out like they know each…
Omg how did I forget this trope. That is one of the basics in dramaland and we never got to see them mocking childhood connection trope in this, so maybe we will really get that somewhere in the story, lols
Can it be that, she is not dead, but playing hide and seek with her sisters? (of course with the help of someone) Maybe the winner/s will get a part of inheritance from her.