There are countless screenwriting gurus and mentors, each with their own valuable nuggets of advice on how to write a viable screenplay. One of the things they all advise in one form or another, is to know what your script is really about. Not how the plot progresses, but why you’ve written it that particular way.
That sounds terribly trite and simple, yet it’s often one of the most difficult and important things to articulate consciously. Especially if you want to avoid generic, hack writing.
Whether you call this theme, premise, story promise, designing principle, controlling idea, it all boils down to the same thing, which I’ve decided to call the DNA of the story. By that I mean a basic, abstract, philosophical understanding of what you’re exploring in the story. It doesn’t refer directly to the specifics of characters or plot, but it does describe the basic question or statement to which everything in the screenplay relates.
Scientifically, this metaphor probably makes no sense whatsoever. In fact I don’t pretend to know the first thing about genetics. But I find the commonly used meaning of DNA useful for maintaining a focus during the writing: An individually configured set of potentials, present in every cell of a living organism, according to which everything in the organism grows.
If on a fundamental level, each and every aspect of your screenplay stems from the same idea, then you create a very pleasing and engaging kind of unity. You’re able to let your characters lead you wherever they want because you know which aspects of what they show you are relevant and which are not. You’re able to make intelligent, original choices about locations, conflicts, dialogue, and so on, because you know what you’re exploring.
Your story DNA might be a bulleted list of questions. It might be a pithy political or psychological statement. Perhaps it’s a nagging ethical question or some futuristic speculation. It doesn’t matter exactly what form it takes, as long as you, the writer, can use it as a touchstone during the writing process.
I’m off to genetically modify my latest brainchild.