The Three Act structure is the base for any story, there's no questioning it. It is a formula that has withstood the test of time, and with good reason. Any story can be split into a setup, conflict, and resolution, even if there are slight variations like a raconto where the conflict is shown first.

However, I find this a bit lacking for story planning in particular, even if it suffices for analysis. Sometimes a conflict seems to have been resolved, but simply must be tackled another way. That's why I cradled a Six Act structure contemplating the possibility of a failed attempt: The protagonist thinks they've lost, the antagonist thinks they've won, and a new status quo is erected, which might give the protagonist a chance that they didn't have before.

I believe this to be a useful guide for falling and rising tension. That said, by no means do I claim authorship of such a method, nor do I think it infallible or suited to every author and every story. It is but a sincretism of other tried-and-tested structures, which simply turns out to be useful to me in particular.

Act I: Setup

• Present characters, what they lack, what they want.
  • Meet future allies, even if they seem like enemies or rivals for now.
    
• Build up some setting as needed, but not too much.
• Foreshadow some events.
• Establish a normalcy: In respect to the conflict, to the main incident, to a theme. Characters still don't know much about any of these.

Act II: Tension

• The conflict or incident happens or is discovered to have happened.
  • Preparations are done to counter it or investigate it.
  • Tensions flare among different factions.
    
• State the theme as a suggestion or a question the characters don't yet understand.
• Establish possible traitors: One with visible motives and unclear honor; one with unseen motives, but apparently impeccable honor.

Act III: Attempt

• The theme's theory is put to the test. It might seem false, then start sounding truer.
  • Different characters represent different "angles" of the theme (e.g., in a story about Justice, one character might believe in "mercy" while another believes in "revenge").
• A first attempt at a resolution or a hypothesis at solving the conflict or incident is tried out, but it ends up failing.
  • The traitor is revealed. The plan was doomed from the start.

Act IV: Deliberation

• "All is lost" moment:
  • The theme's worst alternative is the undeniable truth.
  • The conflict can never be resolved.
  • The incident can never come to light.
• Minor allies might die, or go away, or be discovered to have died in the previous act.

Act V: Confrontation

• A new revelation moves the characters to test new theories, or the old theories from a different angle.
  • The theme starts to make sense again, the incident has a clear culprit, the conflict seems solvable.
• With this, a new attempt is made.

Act VI: Resolution

• In the finale, the characters must make a choice:
  • It definitively proves which side of the thematic debate is "right" within the world of the story.
  • The case or conflict is solved, for better or worse.
  • Greater allies might have sacrificed their lives to achieve this, or retire for good.