Hero's journey
A staged narrative structure derived from Joseph Campbell's monomyth: call, trials, transformation, return.
The hero's journey is a narrative structure derived from the "monomyth" mythologist Joseph Campbell identified in The Hero with a Thousand Faces (1949): myths worldwide would tell one same voyage — ordinary world, call to adventure, refusal, threshold crossing, trials, ordeal, reward, transformed return. Screenwriter Christopher Vogler adapted it into twelve operational writing stages, now an industry standard.
Its strength is coupling external structure (the events) with internal structure (the hero's transformation): each step of the road is also a psychological step. Its limit is well known: applied mechanically, it produces interchangeable stories. It's a grammar, not a story.
Example
Frodo: the Shire (ordinary world), the Ring (call), Moria and Mordor (trials), the impossible return.