Screenwriting professors, analysts, producers...they often talk about "unity." What does that mean?
In screenwriting, unity is the existence of a central designing principle. It's that property a screenplay has when each of its functioning pieces -- character arcs, plot arcs, and theme -- operates in the service of a central principle.
Sometimes this principle is called theme -- other times it's called "controlling idea". But whatever you call it, it's that thing the script is "about".
Finding theme and developing unity...not high on most writers' lists. Most writers will write a script once they have a working premise. Add some characters they've got in the chute, or characters to order based on the market place, some standard transformations...and that's that. And that's fine, if you can do that. If you can write with only that, and muddle through a first draft, then you're ahead of the game.
Once you've written, finished, and spruced up your script -- the next step is to find the theme. This is something Stephen King does, when he writes. He'll blunder through his first "crap" draft, type THE END -- then and only then will he start analyzing it. And this is what you should do.
You sit down and figure it out. What is this thing about? The best way to do this is to summarize your script without referring to the plot at all. Write a summary without citing specific plot elements.
"This is a story about..." For example:
A story about a group of people who fight a galactic evil. It's a story about friendship, love and sacrifice, and how these -- combined with good old pluck -- can bring down the worst evil imaginable.
Not such a hot one. Star Wars, despite its archetypal underpinnings, despite how entertaining it is, doesn't have a great deal of unity. It's pretty much pure plot. Its characters barrel forward with reckless abandon and an almost crazy indifference to the consequences...and only Han Solo shows the slightest glimmer of individuality.
A movie about family. And the lengths to which one will go to create family, preserve family, and protect one's family from threats. These elements are all reflected in the various subplots and character arcs.
The Shawshank Redemption
Shawshank has real unity. It's a movie about freedom. By paradoxically being a movie about the many different kinds of prisons in which we find ourselves. The full development of this theme spawns the plot arc, and the character arcs.
Its unity touches everything in the movie. It's a prison movie about freedom, and about the ways people will seek their freedom from within their own various kinds of confinement.
Script unity means that you arrange each character arc, and each plot thread, to embody the theme of the script, and to comment upon or contrast with every other arc and thread.
Andy comes into prison wrongly convicted, but with a hope for freedom. Which he pursues over the long years, until he finally wins it. Along the way, he experiences various "states" of imprisonment -- mainly due to his talents, which render him useful to the guards and warden. Though these talents afford him a certain degree of freedom, it's not true freedom...he's still firmly imprisoned. Just as many of us feel after twenty years on the job.
Red comes into prison rightly convicted, with no hope of freedom. He's been imprisoned by a rash youthful act, and his hope has gone. So he does what he can within the system, engages his resourcefulness, and finds a purpose as a man who can get things. His association with Andy threatens to awaken hope within Red, but Red rejects that. Until Andy escapes. Thus inspiring Red to escape the prison of his own ideas, to "give up", in a sense -- thereby winning true freedom at last. And a sunny destiny on a Mexican beach with his old friend.
Brooks yearns for freedom. An old trusty, institutionalized, he still cherishes freedom in many forms. For example, in the form of a small bird he can feed and raise...who can come and go, yet remains by his side. Brooks is firmly imprisoned, comfortably imprisoned -- real freedom comes unwanted and rings false. Outside the walls he's imprisoned by his ignorance and inexperience. He can find no purpose alone in a world without bars, and soon loses the will to survive. Freedom, for Brooks, is the worst prison sentence of all, and ultimately crushes his spirit completely.
Even the warden, who smugly believes he is free, is in fact a prisoner of his own corruption. When the truth escapes into the light of day, the warden cannot face the prospect of winding up on the other side of the bars -- so he takes his own life.
The Importance Of Unity
In a movie with real unity, you can find these thematic threads in all characters and plots. This is how you know that a movie is well-designed. And a movie so well-designed usually finds a symbolic resonance in the minds of its audience. The audience finds it moving and significant because of that symbolic resonance -- because its meaning is designed, planned, woven in.
Shawshank reminds us of our own lives. We all know what it's like to feel like we're in prison. Rightly or wrongly convicted. Desiring or avoiding true freedom and its responsibilities. Devoted to goodness and helpfulness...or to coercion, violence and corruption. We can see ourselves and our qualities in a movie like this. The movie allows us to externalize these aspects of ourselves and observe their interplay in a safe environment. In the dark, where others cannot see our faces. And learn from the experience. That kind of thing is what makes a movie truly valuable, on a personal level.
This unity of plot and character, this unity of the parts to the whole, is what makes a movie truly work. It's what gives a movie value, and greatness. It can even make a movie easier to write!
But that's another article for another day...