Save the Cat
Another popular model for structuring stories comes from Blake Snyder's popular book on screenwriting, Save the Cat. Of course, Blake Snyder goes into much more detail and has a lot of other good thoughts to share, so if this model appeals to you, definitely read his book.
In this book, Snyder presents a story structure model with 15 "beats", as follows:
1. OPENING IMAGE
This is the very beginning of the story. It should establish the tone, mood, and type of story that's going to be told. It shows the starting state of the main character and the world in which (s)he lives.
2. THEME STATED
Somewhere near the beginning, someone in the story will ask a question or make a statement that outlines the theme of the story. It won't be obvious, though, just part of a larger conversation--the real impact of the statement won't be felt until later in the story. However, this is where the theme is established that will play out over the course of the story.
3. SET-UP
The set-up is the beginning part of the story, and it incorporates the opening image and the statement of theme. This part of the story needs to grab the audience and make them want to stick around for the rest. It introduces the characters and shows us their strengths and weaknesses, and points out (subtly) the things in their lives that need to be fixed.
4. CATALYST
The catalyst is the thing that happens in the story that pushes the characters out of the everyday routine. It might be something big and dramatic, like a child being kidnapped, or it might be something much more subtle, like a letter being delivered to the wrong mailbox. But without this moment, there would be no story.
5. DEBATE
In this beat, the main character reacts to the catalyst, evaluates the new situation, and decides what to do about it. It's the first moment of truth in the story, where the main character has to decide to step up and take on the challenge--or run away from it and take the consequences.
6. BREAK INTO TWO
"Two" in this context refers to Act Two. The first five beats constitute Act One. When the main character stops debating and acts, he steps across the threshold from his old life and moves forward into the new world of the story.
7. B STORY
This is the beginning of a major sub-plot, often "the love story". Often, the main character is introduced to new characters who belong to the "new world" of the story (s)he has entered, and begins to learn about how things work outside the comfort of the "normal" world we saw in the set-up.
8. FUN AND GAMES
In this part of the story, things begin to really happen, as the implications of the catalyst event begin to play out. Complications abound, and the main character is caught up in the whirl of it all.
9. MIDPOINT
At the midpoint, the action reaches a peak in which the main character is either "up" (seemingly having reached a pinnacle of joy and fulfillment in the new life) or "down" (the main character's new world has completely collapsed around him/her). However, things are not as they seem, at the midpoint something happens that demonstrates this, and raises the stakes for the main character.
10. BAD GUYS CLOSE IN
The antagonists regroup and get serious. If things were good for the main character, they go bad. If things were bad, they get even worse.
11. ALL IS LOST
Everything comes crashing down. The bad guys seem to win, and the main character(s) must change their way of thinking, let go of the past, and change in some way in order to move ahead into the future. This part of the story often includes a "whiff of death." Someone in the story (especially a mentor) might die, or come close to death, or it might be more subtle and symbolic, like a flower or goldfish that dies. It reminds us that the old way of being is "dead," there is no going back, and from here out, everything will truly be different.
12. DARK NIGHT OF THE SOUL
This beat shows us how the main character feels about all hope being lost. It is the darkest darkness before things change and dawn begins to break. This shows the despair of hitting rock bottom.
13. BREAK INTO THREE
Act Three, that is. The answer is found! The B-story characters come through, or the main character finds the humility to change, or whatever. The real problem is identified, and a real solution for it is found at last.
14. FINALE
The solution is put into practice, and everything changes once again. Victory is real this time, and the main character has become someone who can truly appreciate it.
15. FINAL IMAGE.
The final image shows us the result of the solution--the way the world is now better, and has reached a new point of stability and routine. Everything is different, but in lasting, positive ways.