This is a story of a girl, who met her PAST and FUTURE. Park Ji Goo, from the present, is so shock of seeing her other selves. 

"Why are you here!?" Ji Goo asked.

"Ji G--" Ji Goo was cut by Ji Goo

"Ji Goo from past! Don't you dare to keep it a secret that we're here to warn her!" the future cut her off.

"Warn? About what?" Ji Goo asked.

"You--" Ji Goo  was cut again by her future self.

"Oh My God! Don't ever dare not to tell her that someone is going to kill you!" she cut her past self. 

"Then what'll happen if my past self die?" Ji Goo asked.

"Of co--" she was cut again by her future self.

"Of course the three of us will die since she's the first one to be born. Duh!" Ji Goo