Freytag's Five Act Dramatic Structure

Freytag suggested a five act dramatic structure, usually for screenplays but also related to films and music videos, for example. It is usually shown as a pyramid.

The first act is the exposition, which introduces the characters, settings and plot. This usually ends with an incident.
Act two shows rising action, which complicates the problem created by the exposition.
The third act is a climax, where the plot reverses, for example going from lucky to unlucky, or the other way around.
Act 4 is when the results of the incident play out, usually a conflict which puts the ending in doubt.
The fifth act is the denouement, which shows the consequences of the conflict or incident playing out.