One secret that will make the task seem less ominous, is to think of Act Two as being divided into two parts. This is also why many screenwriting gurus refer to a "Four-Act Structure".

If you chop Act Two neatly down the middle, right about page 60 in a standard 120-page script, you are left with two smaller 30 page sections. If you approach these sections as proper acts in their own right, each with a beginning, middle, and climactic end, then you have a much clearer and easier structure to work with. These "subacts" will tend to break each half of the second act into three distinct "subsections" of approximately ten pages each.

The page 60 dividing line also presents you with a concrete goal to work towards as you write the first half of Act Two. This dividing line should also be represented by a defining event which neatly bisects the film into two distinct halves.

To illustrate, here is a breakdown of the second-act structure of "Alien":

"Alien"

• First 1/2
  Subact 1: Science officer Ash attempts to cut the alien larva from Kane's face, but the creature leaks acidic blood which burns through several decks.
  Subact 2: The larva leaves Kane's face, and is found to be dead. The lander leaves the planet.
  Subact 3: An alien baby that has incubated inside Kane's body bursts from his chest and hides somewhere in the ship.

• Midpoint: The crew decides to hunt down the alien.

• Second 1/2
  Subact 1: While searching for the alien, crewman Brett is killed by the creature, now grown much larger.
  Subact 2: Dallas, the captain, attempts to hunt the alien down inside the ship's duct system, but is killed.
  Subact 3: Ripley, now in command, finds out the Company's secret directive to preserve the alien at any cost. Ash, following the directive, attempts to kill Ripley, and is discovered to be an android.

Notice that now that the main body of the script's action has been outlined, you can see that it it comprised of a series of distinctive events which break the story into definite blocks. When you are outlining your own stories, think of them in terms of these small blocks, or subacts, that are then used to build full-fledged acts, which are then used to build the entire story. This is the essence of the Divide and Conquer strategy. When you look at the story as a collection of small pieces, it becomes much less intimidating to assemble an entire screenplay.

As you can see, the structure of "Alien" is extremely straightforward, yet effective. The film, being more about situation than character, is based upon a relentless series of irreversible actions. This makes for a taut, clockwork plot which hammers the story home.

A pointed feature of the "Alien" script is that the description is clipped, and the dialogue terse. Anything non-essential is stripped away in order to move the story forward.

Notably, "Alien" has no subplots.