How to Structure Act Three of the Three Acts
The third act is the completion of the story; showing how the conflicts involving the characters are resolved. The overall situation, and elements thereof that make up the story, are concluded. Some strands of the narrative can be left open, either for sequels or just to demonstrate that life is not always neat and tidy, but the main story arc needs to end here.
Within Act Three there are four key elements, just as there were in the first act. These bring the story to an end, and if one element is missing the third act will feel lacklustre and unfinished. As with the first act, they do not need to be at the end of the story as you can move the narrative around, as Quentin Tarantino did in Reservoir Dogs (and pretty much every film he has made since).
The four things that make up the third act are: the New Tension, the Twist, the Final Culmination, and the Resolution. In Act Three, the question that was answered in Act One is answered as the plot lines from Act Two converge.
The New Tension
At the end of Act Two the plot reached the main culmination, and the protagonist has effectively reached their destination, whether that was physically, emotionally, or spiritually. At the beginning of the third act a new tension is introduced, as the subplot that was running throughout the second act collides with the main plot.
In Stephen King’s The Shining, the main plot has dealt with Jack’s descent into madness. The subplot has involved his son, Danny, who has psychic abilities. At the end of the second act Jack is locked in a pantry, but for the first time the hotel shows it can control matter by unlocking the door and letting Jack out in exchange for him agreeing to kill his wife and son. Danny is able to send Dick Hallorann a psychic message to come and save him from his father. The new tension is then introduced as Jack goes to murder his family, whilst Dick races to the hotel to try and save them.
As a result of the new tension, and the main plot and the various subplots coming together, the story takes a turn. The level of twist can be anything from a minor adjustment to a complete about change in everything that has happened before; it is entirely up to you as the writer.
In the Usual Suspects, which features a well-known Act Three twist, Dave Kujan has been interrogating Verbal Kint. The subplot of Agent Jack Baer’s investigation into the aftermath of the boat massacre crashes into the main plot of the interrogation, including the flashbacks, as the only survivor is able to describe Keyser Söze to a sketch artist. That sketch comes through as Dave Kujan notices the information on his wall that Verbal has been staring at throughout the film, and confirms to the viewer Dave Kujan’s realisation.
In True Grit by Charles Portis the twist comes as Mattie, the protagonist, fires a rifle and the recoil causes her to fall into a mineshaft, where she is bitten by a snake. Rooster Cogburn has to ride throughout the night to get to a doctor and save her life. This results in her losing an arm, although that final element was left out of the film adaptation starring John Wayne. The fact that Rooster saves her shows he cares more than just about money, demonstrating his change in character.
The Final Culmination
After the twist, the story all comes together. The final culmination is that big moment we have all been waiting for. In Star Wars, this is where they destroy the Death Star and save the galaxy. We’ve known it was coming all along, we’ve waited for it; we need this scene. The hero and the villain face off for a final showdown which will end the story completely.
In the novel Room by Emma Donoghue, the story follows Ma and Jack, who live in and eventually escape from a room in the back garden of the man who has held Ma captive, Jack’s father. As Jack is young he is able to adapt to normal life, eventually, even though he has never been beyond that room, yet Ma struggles with the outside world. The Final Culmination comes as Jack asks to go back to the room, and Ma takes him to see it. Jack realises the room which had been his whole world is in fact incredibly small, and is surprised at how his horizons have expanded so much. He says goodbye to the room for the last time—as does Ma—and they can finally, together, leave it behind them.
This is where a new status quo is established, much like the status quo which existed at the beginning of Act One. The story has finished. The characters may have changed, the world may have changed, but the story itself has now reached its conclusion and we are left with the new normal.
For Mattie in True Grit this is her, as an adult, alone, with one arm, discovering the man who saved her life, Rooster Cogburn, has died. In the Usual Suspects it is the final realisation that Keyser Söze got away with his crimes, as he always does, but now his face is known to the authorities.
You don’t need to resolve everything as long as the particular story you are telling is completed. The Shining by Stephen King leaves some plot threads open, and the film by Stanley Kubrick even more so, but the main threat of the story, Jack Torrance, is dead. Whether what possessed him—be that the hotel or something else—is still out there is of no consequence. The boy and his mother are safe. That is the resolution.