Three Act Structure

From Guidevines

The story structure of most short stories and films (which are the equivalent of longer short stories in number of events). Shorter novels, or those with extremely horizontal stories, may use this simpler structure, rather than the five act structure.

The "acts" are not strictly those of theatre, but are subdivisions of the story where certain parts of the story arc develop. They are sections determined by what happens in them, not where chapter divisions or other artificial structures fall.

Act I (The Beginning) consists of introduction of characters and milieu, the set-up, and the introduction of the problem of the story. Film and fiction being different media, these will be handled differently: for example, film can easily show a normal day behind the titles where detailing this up front would slow fiction to a degree not usually acceptable today.

In Act II (The Middle), complications arise as the protagonist's attempts to solve the initial problem create other problems and/or fail while the problem worsens. This act contains a turnaround, where the protagonist realizes either the problem is different than they thought, that friends and enemies are not what they thought, or that their approach or self-knowledge needs change. Alternately, the turnaround may be that they have gotten themselves into a new problem from trying to solve the original one. For example, investigating the disappearance of a friend may lead them into a plot to take over the world. They know now what happened to the friend (dead or imprisoned or part of the plot): the turnaround is that they must now stop this plot.

Act III (The End) contains the crisis and climax of the story, based on the turnaround, followed by the denouement.

The story arc of tension is a simple one of a fairly direct climb to the climax with the fall-off at the end.