Your screenplay is really just telling one story. Since you can’t tell a single story for two hours, you emphasize your main story by telling multiple stories, usually subplots, that reinforce the main story.
In “The Curious Case of Benjamin Buttons,” a man (Brad Pitt) ages backwards. To reinforce this backwards idea, the beginning tells a story about a man who lost his son in World War One. So he builds a clock that runs backwards as a symbol of hope that all their lost sons could turn back time and come home again.
This backwards running clock reinforces the idea of Benjamin Buttons aging backwards. Just aging backwards is more of a gimmick than anything else. (Just read the original F. Scott Fitzgerald short story, which bears little resemblance to the movie.) To make this idea of aging backwards more important, the main theme of the movie is about experiencing life and living. As Benjamin Buttons starts out as an old man, he lives in a nursing home where old people die periodically, which teaches him how fragile life can be.
As comic relief, he periodically runs into someone who claims to have been hit by lightning seven times and each time describes a different way he was struck by walking, on a roof, riding a tractor, etc. This humorous bit keeps repeating the nature of how life can change so quickly.
Later as Benjamin Button’s girlfriend is in Paris, he explains the cascading list of events that could have happened, but didn’t. These seemingly random moments wound up with his girlfriend getting hit by a car and breaking her leg in multiple places, ending her dancing career. This story once more emphasizes the haphazard nature of life and the importance of treasuring every moment.
Benjamin Buttons has an affair with a woman who once tried to swim across the English Channel but failed. She vowed to try again but never did. Then a few decades later, Benjamin Buttons sees a news story about an old lady who swam across the English Channel, and he’s delighted to see that it’s the woman he had an affair with. When this woman broke up their affair, she simply left a note that told him, “Nice to have met you,” which again reinforces the fleeting nature of life.
As Benjamin Buttons gets younger while his girlfriend gets older, he makes the decision to leave so his girlfriend won’t have to take care of him as a little boy. He travels the world to experience different adventures. Eventually, he returns back to the nursing home where he grew up, slowly becoming more child like until he becomes a baby and finally passes away.
“The Curious Case of Benjamin Buttons” is a slow movie, but fascinating at every moment because it keeps emphasizing the fleeting nature of life and how life is worth living through experiencing pleasure and achieving dreams. In your own screenplay, find a way to keep repeating your story’s main theme.
In “WALL-E,” WALL-E wants to find love and so do the human couple WALL-E helps bring together. In most movies, the hero and the villain are pursuing similar goals that repeat the theme of the movie. In “Star Wars,” Luke and Hans Solo are both looking for a higher purpose to their lives.
Decide on one story you want to tell, and then find the meaning behind that story. Your story’s physical goals are trivial, such as the idea of a man aging backwards in “The Curious Case of Benjamin Buttons.” What makes that movie so fascinating is how it uses the idea of aging backwards to teach us how to view life from both the perspective of someone getting older and someone getting younger. This new perspective, presented in multiple ways, tells us a complete and satisfying story.