The Three-Act Structure

Syd Field was a screenplay teacher and created many popular methods, one of them being the Three-Act Structure. The structure consists of three acts with them being called the Setup (Act I), Confrontation (Act II) and Resolution (Act III). Act One sets ups the world, characters, the character's goals, as well as the conflicts/obstacles that are preventing them from achieving their goal, this consists of 25% of the film. Act Two raises the stakes for the characters to reach their goal by escalating the conflict, this consists of 50% of the film. And Act Three, which resolves the story with either success or failure, this consists of 25% of the film. The Inciting Event starts the characters journey, it introduces them to what they need to achieve. This usually is 12% of the way into the film. Plot Point 1 is the point of no return and which the characters truly start their journey. This is the transition between Act One and Act Two and is 25% of the way into the film. The Pitch Point is at the start of Act Two and it is the first of many obstacles the protagonist must face. It is also a good time to introduce the antagonist and to set up the midpoint. The midpoint is when you think the characters have won. Then, shortly after, is the crisis. This is when the characters are now at their lowest and are now ready to fight back. The midpoint is half way in the film and the Crisis is 65% of the way into the film. And finally, the climax and the resolution. The climax brings everything together between the characters, either resolved by a fight or a talk. The resolution then ties everything up usually on a happy or sad note. This is the last 90%-100% of the film.

Alien: The Three-Act Structure:

Act 1:

The spaceship Nostromo is on its way back to earth with 20 million tons of mineral ore. The characters wake up from a hyper sleep thinking they are nearly home but after Dallas speaks with MOTHER, the ship's course has changed because it has picked up a SOS signal. They go down to the planet to investigate to find an unknown spacecraft. While investigating the ship, Kane discovers multiple egg shaped objects and goes to have a closer look at one. As he goes to do so, a strange lifeform jumps out of the egg and attaches to his face.

Act 2:

They rush him back to the ship to try and save his life but Ripley is very unsure as it breaks the quarantine rules. They try removing the alien on Kane's face but it tightens its grip. Further research shows that the alien is feeding Kane oxygen and trying to remove it will kill Kane. Everyone goes back to their posts and Ash is left with Kane. The alien then removes itself from Kane's face. They start looking for it and eventually it falls from an overhead department onto Ripley but it appears dead. They leave the planet and carry on their journey back to Earth. Kane awakens and they all have a meal before they go back into hyper sleep. During the meal, Kane starts to choke and acts very violent. The crew try pinning him down as he is screaming in pain on the table but all of sudden a creature bursts out his chest, jumping out and escaping down a hallway. The crew split into two teams to try and capture the creature, but the creature has grown and killed Brett. They group back together and they come up with an idea to use flamethrowers to get it into an air lock which Dallas volunteers to do so. The alien outsmarts them leading to Dallas' death. Ripley is now in charge and talks to MOTHER for answers. She finds out Ash had changed course to investigate this new lifeform. A fight breaks out between Ash and Ripley with Ash almost killing Ripley, but Parker kills Ash revealing he is actually an android. They connect a computer to Ash's head to find out how to kill the alien. He says you can't kill it, it's a 'perfect organism'. They then decide to self-destruct the ship and escape in the shuttle. Ripley prepares the shuttle and the self-destruct system while Parker and Lambert gather supplies. While doing so they are cornered by the alien and killed. Ripley gets on the shuttle and the Nostromo self-destructs.

Act 3:

Ripley prepares for hyper sleep but finds the alien stowed away. She runs into a locker and finds a spacesuit and comes up with an idea to fire the alien out the ship. The alien doesn't see her as she slowly exits the locker and straps herself to a chair. She opens the door and the alien goes flying out the door but holds on. Ripley uses a harpoon to push it out into the vastness of space leading it to blow up. Ripley records a final log entry stating that everyone is dead, the cargo and ship are destroyed and that she expects to reach the frontier in six weeks. She signs off as Ripley, last survivor of the Nostromo, and gets into hyper sleep for the journey back to Earth.

Plot Point 1: The characters going to investigate the unknown ship.

Pinch Point: The alien attaching to Kane's face and the crew trying to remove it.

Midpoint: The alien removes itself from Kane, he awakens and they have a final meal before they go back into hyper sleep.

Crisis: The alien bursts out Kane's chest, escaping and killing him.

Climax: Ripley blows up the ship but releases the alien snuck aboard.

Resolution: She kills the alien by opening the ship door and the alien flying into the vastness of space.