Narrative Theories

Propp
Came up with the theory that characters in a story take on specific roles or functions. Propp came up with 7 character types usually found in a narrative (a character could adopt 1 or more of these roles); the Hero (restores narrative equilibrium by embarking on a quest), the Villain (creates the destruction/chaos), the Donor (gives the Hero something to help restore balance), the Helper (aids the Hero in some way), the Princess (usually has to be saved), the Dispatcher (sends the Hero on their task) and the False Hero (appears to be good but turns out to be evil).

Todorov
Todorov came up with 5 stages he thought would be found in the narrative of a text, and tend to be found in most mainstream ones. These stages are as follows;
1. a state of equilibrium at the beginning
2. the disruption of the equilibrium
3. a realisation that there has been a disruption
4. an attempt to repair the disruption
5. the restoration of the initial equilibrium or a new equilibrium

Barthes
Barthes came up with 5 codes which he thought were in any narrative. These 5 codes are as follows:
Enigma Code - Something the audience does not know.
Action Code - Something the audience knows and don't need explaining.
Symbolic Code - A structure which organizes meaning such as through the use of binary opposites (good/evil, war/peace).
Semic Code - Using hints to connote certain concepts such as a man wearing a suit in a mansion with classical music playing connotes wealth.
Referential Code - Looks at the audiences wider cultural knowledge, morality and ideology.

Levi-Strauss
Saw narrative structures in terms of binary oppositions; sets of opposite values which reveal the structure of media texts. For example, earth/space, new/old, light/dark... He was not interested in the order events were arranged. Themes can contain a variety of oppositions; Sci-fi films may contain earth/space, good/evil, human/alien etc...