The fabula of a story is the universe within the plot itself. Such a universe is a work of fiction. Anything can happen, be it realistic or not. Every time a book is read, the events in that book take place again: a character will die every time the book is read. Such events must be referred to in the present tense, since they are always happening. Events in the fabula of a story may also have happened previous to the timeframe of the story itself. In this case, such an event can be referred to in the past tense, as the reader will never get to see such an event take place.