The Elements of Three Act Structure

Today I want to discuss the main elements of three act structure. There are several thousand places you can learn the basics of three act structure so I will try not to simply repeat here what you can easily find elsewhere. A note on naming conventions – there are lots of terms for some of these elements. I think everyone who writes a book creates their own so it seems more original. I will use my favorite terms.

Prologue – a prologue is an opening scene or sequence which serves no significant plot purpose. That does not mean, however, that it serves no purpose at all. Prologues are used to set tone, introduce character and/or pull the audience into the story. They can also introduce elements like the supernatural which will come into play later but must be shown early so the audience isn’t pulled out of the story. Note: if you’re paying attention to expected page count for the acts, the prologue should not be credited against act one. It is a separate entity.

A classic example of a prologue is the great opening sequence of Raiders of the Lost Arc where Indy recovers the idol from the cave. A first time viewer could start the movie with Indy in the classroom and not even realize anything was missing. But imagine how boring it would be to sit through those university scenes if we weren’t shown the excitement and adventure we could expect to come later.

Act One – Act one is usually about the first quarter of the movie. It sets up the story by introducing the character, his dilemma and the stakes.

Domino – This is my one original addition to the three act structure theory! I came up with it because students in my class were sometimes getting confused about the Catalyst. The domino is an event which sets the story in motion but does not rise to the level of catalyst. I call it the domino because it’s like the first domino in a series that falls, knocking down the next one and so on.

Catalyst (also called inciting incident, precipitating incident or point of attack) – This is the moment when the character has their dilemma. It’s the scene where the audience gets a sense of the arc of the story (see main conflict later). Note that neither the character nor the audience needs to fully understand the scope of the dilemma yet; they simply must realize that it exists.

In Star Wars, the catalyst is when Luke sees the hologram of Princess Leia and decides he must help her. Even though Luke doesn’t know how big a problem he has, we the audience know Leia has been captured by Darth Vader and anticipate big trouble. The domino in Star Wars is when Leia puts the plans into R2D2 and sends him off to Tatooine. That sets the story in motion but does not qualify as the catalyst because our hero is still working on the farm, not involved in the story at all yet.

Act One Break (also called first turning point or break into two) – This is the moment when our hero embarks on his journey to solve his dilemma. Between the catalyst and this moment, he may have been trying to find a way to avoid the problem or making preparations for the challenge. This is the place where he actually sets out to solve the problem. In Star Wars, Luke agrees to go with Obi Wan.

Act Two – Act two is roughly the middle half of the movie. It is where writers often have the most difficulty, usually when their obstacles aren’t complex enough to sustain this long act.

Midpoint – Somewhere near the middle of act two there is usually a big event that twists the tension of the movie in some way. We don’t want our story to be too linear. The character needs to have ups as well as downs, to get closer and farther away and closer again to his goal. The midpoint usually introduces some new element or sub-goal to keep things moving. It’s also usually the opposite of the Act Two Break in terms of the character’s success or failure.

Act Two Break (also called second turning point or break into three) – This is often called the character’s lowest moment. I think this is a misnomer, however. Immediately after the break, things usually get worse, not better. Rather, the act two break is the place where things go most wrong for the character, often the point of the character’s biggest failure. The next sequence of the movie shows the aftermath of that failure and leads to the real lowest moment just before the Twist (see below).

Act Three – Usually the last quarter of the movie, though if any act should come in short, it should be Act Three. This is the race to the end. The pace picks up and we really shouldn't be introducing any major new elements or exposition.

Twist – This is a confusing element. I do not mean a twist like in the end of Sixth Sense, though those can be powerful. The twist from a structural standpoint is the moment when the character figures out how to resolve his dilemma (in a movie with a happy ending).

Resolution – Simply, how the character’s dilemma is resolved. Most importantly, this is the end of the tension of your story. From here on out the audience’s involvement will quickly dissipate. You have a little time to wrap things up and supply an emotionally satisfying denouement, but you better be pretty near the end when you resolve the dilemma.

Main Tension – This is the central idea of your story, what drives it forward. I find it best to phrase it as a question. Star Wars: “Will Luke Skywalker save Princess Leia?” Matrix: “Will Neo defeat Agent Smith?” Amelie: “Will Amelie find love before it’s too late?” It should be simple and primal.

The Main Tension is asked at the Catalyst and answered in the Resolution. It’s what defines the story for the audience.

There are other, smaller tensions in the movie. Each subplot has a tension that could be mapped out in its own three act formula, though the beats would fall in different places. Act Two should also have its own tension, and individual sequences and scenes have tensions. Identifying the tensions that are pulling the audience through the film is very useful to the writer.

There are some common ways in which three act structure works. If the story has a happy ending, the midpoint is often an up moment, act two break is a down moment and the ending, naturally, is up. However if the story has an unhappy ending these beats are reversed. Think of the classic American gangster movie showing the rise and fall of a criminal. The midpoint is usually a down moment, but at the end of act two he’s seized control of his criminal empire…before it all collapses in the resolution.

Another common form is where the character gets what they want at the end of act two, but they no longer want it. Or, in trip-with-a-destination movies, the character arrives at the destination but things aren’t what they expect. I’ll give some examples of these forms in future posts.