Definition: Formula that holds a screenplay should consist of three parts—1) Set-up, 2) Confrontation and 3) Resolution—each with the same particular rules.

History: The term’s origin was the three-act play. Tragedy, wrote Aristotle in , “is a representation of an action that is whole and complete . . . A whole is what has a beginning and middle and end.” The beginning need not depend on anything before it, but because of it “something else exists or happens.” The middle deals with consequences of this and culminates in another “something else.” The end is “the natural result of (the second) something else but from which nothing else follows.”

In film, “Three-act” refers to three groups of scenes—the Set-up (Act 1), Confrontation (Act 2)  and Resolution (Act 3). The formula is commonly recognized in romantic comedies as: “Boy meets girl. Boy loses girl. Boy gets girl.”  Regardless of the genre, each “act” has the same set of particular rules. (Filmmaking proviso: “It’s a rule until you successfully break it.”)

Act I: Setup

This “act” introduces the main characters and their place in a contemporary, historical, future and/or fantasy reality. There also occurs an incident that causes the protoganist(s) to react—a reaction that leads to an incident more dramatic than the first.  Rules include:

1. Physics: At the beginning of movies the audience is disposed to suspending its disbelief. If the laws of nature in your fictional world differ from the factual world, alert your audience to this during Set-up. Establishing what is and what is not physically possible is prerequisite to successful plot development.
   
   
2. Chance: The protagonist may benefit or suffer from intervening chance only during the Set-up.  After that, the audience expects characters and circumstances to drive the plot. Of course, this begs the question: What about the bombing of Pearl Harbor in “From Here to Eternity” (1953) or the collision with an iceberg in “Titanic” (1997) or the volcano erupting in “Volcano” (1997)? All were intervening incidents occurring after the movies’ Set-up phases.

   And yet, from scene one of these films, who did not know that Pearl Harbor would be bombed or Titanic would be sunk or a volcano would erupt? History provided this Set-up content for “Eternity” and “Titanic.” Watching the beginning of “Titanic,” for instance, we recognize as very bad luck Jack (Leonardo DiCaprio) winning a hand of poker whose pot is passage on the Titanic. Non-historical films like “Volcano” follow a similar pattern, namely that audience foreknowledge of an impending incident is effectively Set-up content. Who seeing a movie titled “Volcano” would not expect to see a volcano? That said, in “Volcano” and other movies of the “disaster genre”—e.g., “Towering Inferno” (1974), “The Perfect Storm” (2000), San Andreas (2015), etc.—the disasters occur in, begin with, or are foreshadowed by Act 1.

   
3. First Plot Point: This incident initiates the plot. The incident particularly impacts the protagonist(s) and other characters as opposed to an incident that impacts other people not portrayed in the movie. It is an event that spurs the protagonist to act and set in motion a chain of events. Significant action can occur before the inciting incident—e.g., James Bond (Sean Connery) blows up a narcotics factory  in “Goldfinger” (1964); Indiana Jones (Harrison Ford) escapes a jungle temple and headhunters in “Raiders of the Lost Ark” (1981);  John Miller (Tom Hanks)  and his squad land in France during D Day in “Saving Private Ryan” (1998). The inciting incidents in these movies were: Bond is knocked unconscious and awakens to find Tilly Masterson (Shirley Eaton) dead and painted gold (“Goldfinger”), Indiana is retained by Army Intelligence agents to travel to Tibet and locate his Egyptologist mentor (“Raiders of the Lost Ark”), and Miller is ordered to find and transport to safety a private whose three brothers have died in action. On the other hand, an inciting incident need not even be shown on screen. For instance, the inciting incident in most mysteries is a murder we know about via the protagonist who is either investigated or is the investigator,
   
   
4. First Plot Point or Turning Point: The Set-up ends with an incident that will drive the protagonist’s conduct throughout Act 2 or the “Confrontation.” Called the “First Turning Point” or “first plot point,” this incident compels the protagonist to pursue a course of action: e.g., find the real murderer to clear my name; win the love of someone who despises me; never (as God is my witness) be hungry again, etc.

Act 2: “Confrontation”

Act 2 is devoted to the protagonist trying to understand and resolve the situation arising from the first turning point.  This takes time because every protagonist is on a journey of innocence to experience. Aided and opposed by other characters, the protagonist must acquire the knowledge, skills and/or self awareness needed to achieve a resolution. This character development constitutes the “character arc.” At the other end of the arc is the Second Plot Point, a.k.a. Second Turning Point, which involves the protagonist understanding all and knowing what to do about it.

1. Subplots:  These are introduced in Act 1 and Act 2,  and usually conclude in Act 3. They offer an alternative way to disclose backstories, traits, attitudes, opinions and relationships of characters. The rule is a subplot must prove relevant to the main plot.
   
   
2. Second Plot Point: This ends Act 2 and begins Act 3. It is more commonly known as the climax. Quite simply, it is here that the killer is exposed, the boy wins the girl’s love, the protagonist saves mankind, etc.

 Act 3: “Resolution”

This act resolves all plot and subplot conflicts. This is normally the shorter of the three acts, particularly when Act 3 is a “Hollywood ending.” Most action in movies is occasioned by conflict; the least action by happiness.  

1. Loose Threads: Be certain all plotlines are complete and main characters accounted for. You do not want moviegoers leaving the theater asking, “But what happened to Larry?”
   
   
2. Payoff or the Rule of Audience Expectations:  A payoff is action that gratifies an audience’s plot expectation. It is most associated with crime movies because the Motion Picture Production Code of 1934 required the following payoff in crime movies: No one who commits a crime gets away with it. Audiences could rest assured that justice would triumph in the end. In the 1960s, however, movies began featuring villains so evil that arrest or a simple death did not satisfy moviegoers’ sense of justice. Even as the Code was losing its teeth, the crime movie payoff was expanding to include: The worst criminals will suffer or die in a horrible manner.

This addition has produced decades of memorable movie moments, e.g. Goldfinger (Gert Frobe) sucked through a jet window at 30,000 feet (“Goldfinger” 1964);  Devereau (Patrick McGoohan), shot and dangling headfirst out of a runaway locomotive, beholds helplessly another locomotive rushing toward his face (“Silver Streak” 1976); thrust through an office  window, Gruber (Alan Rickman) grabs the arm of Holly (Bonnie Bedelia) only to watch McClane (Bruce Willis) break his grip and send him plunging 50 stories (“Die Hard” 1988);  Strannix  (Tommy Lee Jones) is gouged in the eyes by  Ryback (Steven Seagal), who then thrusts Strannix’s head into a live computer monitor (“Under Siege” 1992);  Marko (Arben Bajraktaraj) is strapped in a chair by Bryan (Liam Neeson), who attaches jumper cables to the chair and tortures Marko with electric shocks before turning on the current and leaving Marko to die screaming (“Taken” 2008).

Audience expectations are not limited to crime movies. Take, for instance, a movie in which a boy meets cute a girl who is dating a stuffed shirt. The audience will expect the girl to eventually leave the stuffed shirt for the boy. If she does not, the audience will be dissatisfied unless the plot somehow provides a satisfying alternative. Point being: If a situation is common in movies, moviegoers will likely expect a payoff. To do the unexpected, the filmmaker risks audience dissatisfaction.

Hollywood Lexicon Index