Transmigrated into a Book: Clearing the Name of the Tang Family's Eldest Daughter

[Transmigrate into a book + abandoned by the System halfway through + take charge of a new life + change the ending] I was just feeling sorry for the villain. How did I end up transmigrating into a book out of nowhere? And if I had to transmigrate into a book, why did I have to become a villain? Wait... Isn't Tang Ning, the eldest daughter of the Tang family and a villain, destined to be torn apart by five horses in the end?

To change the ending, I still have to complete the System's assigned tasks... This is just too much.