The Theme or Premise of a screenplay is the message that the writer wishes to express to the audience through the events that happen to the main character as a result of the central conflict in the story.
In The Godfather , the theme could be expressed as “Family loyalty leads to a life of crime”. In The Old Man in the Sea or Rocky, the theme could be “Courage leads to redemption”.
The tricky part about Theme is that the interpretation of theme is somewhat subjective. The writer may see the theme of his story one way and different audience members may see the theme in different ways. The more the writer reinforces the theme in scene after scene, the better the chances are that the audience will see the theme in the way the writer intended.
There can be only one Theme in your story. Every scene you write must express that theme in some way. You can not have scenes that contradict your theme. Let’s that a Nonfiction book called “Dogs Make Better Pets than Cats”, The writer would give example after example of how dogs are fantastic pets and examples of how cats would be terrible pets. The writer should not then throw in examples of how cats make great pets too, because that is contradicting the theme of the book: that Dogs Make Better Pets than Cats.
In a fiction story the same is true; do not create scenes that contradict you theme. In the movie “Hitch”, the theme is Honesty Leads to True Love and this is expressed in scene after scene through out the movie.
Hitch [Will Smith] helps men get out of their own way in wooing the women they truly like. His latest client is the shy, nerdy Albert [Kevin James] who is a successful, nice guy who has no social skills when it comes to meeting women. Albert is in love with a woman totally out of his league, the rich, beautiful Allegra [Amber Valletta]. Hitch teaches Albert how to be smooth and confident and to not do the silly things he naturally does.