The three-act structure is a classic method of storytelling with clear beginning, middle, and ending phases. The second act is typically much longer than the others, and can be treated as two sections divided by a climactic midpoint.
The outline below covers the basics, but you can add as many details as you feel necessary.
ACT I : THE BEGINNING
Sets the tone for the story and introduces the protagonist.
Scenes that introduce the characters’ world, introduce supporting characters, and point to changes to come.
The surprise moment that turns the protagonist’s world upside down and kicks off the main plot.
Call to Action
How do the characters react to the inciting incident? What choice must the protagonist make?
ACT II, PART 1 : THE MIDDLE
How does the protagonist decide to deal with the problem? What are the stakes?
Rising Action / Mounting Problems
Troubles mount as the conflict kicks into high gear. What keeps the protagonist going?
Midpoint / Reversal
A surprise event that wrecks the protagonist’s plan and raises the stakes, often after a temporary triumph.
ACT II, PART 2 : AFTER THE MIDPOINT
There is fallout from the midpoint, continuing the conflict as problems pile up.
A moment when everything goes wrong and the goal appears impossible. The protagonist’s darkest hour begins.
New ideas or fresh inspiration offer hope and set up the story’s final act.
ACT III : RESOLUTION
Plan / Resolve
All the pieces are moved into place for a final climax or showdown. Subplots tie together and the stakes are raised to a peak.
The protagonist comes face to face with the antagonist or main obstacle and is victorious… or fails.
After the climax, the protagonist and/or world have changed. A final scene provides closure to the story.