What is a narrative theory?

A narrative is a story structure, usually in great detail. There are many different types of narrative. These include a normal liner narrative where every piece of the story follows on from one another in chronological order. There is the non-liner narrative which gives story points in the wrong order which may seem not to make sense until the very end of the narrative. There is also the circular narrative where the story seems to start and end in the same place. Often a narrative is meant to include the "whole story." 

A Narrative theory is an idea about how the narrative of stories are typically portrayed in the media of books, television and films. There have been many narrative theories over the century including Propp's, Strauss' and Todorov's.