Akdangui Seulgiroun Euntoe Gyehoek

One day, Lillian Sergenev bumps her head and realizes she's been reborn into a hardcore tragic romance simulation game! As the sister of the game's protagonist, she decides then and there that she's going to change the game by preventing her sister from being locked up by the crazy, obsessive male lead. She is determined to keep the two from meeting at all costs, but what is she supposed to do when said male lead suddenly turns up on her doorstep... as a gift from her father?!

(Source: Tapas)