There is no such thing as an original story, but there is such a thing as telling a story originally. Learn the difference and you won’t waste your time trying to achieve the impossible.
Writers are often paranoid about creating an original story. Essentially, there are no original stories but there are original ways to tell a story. Movies can often tell similar types of stories but with different plots.
“Finding Nemo” and “The Day After Tomorrow” are both about a father trying to find his son, but the stories are completely different.
“Die Hard” and “Under Siege” are both about one guy battling terrorists, but one guy is trapped in a skyscraper and the other is trapped on a battleship. Yet both are original stories not because of the plot or theme, but because of the specific characters, plot, and location.
Don’t waste your time trying to create an original plot or theme. Focus your time on creating original characters, situations, obstacles, and style. On the surface, “Kill Bill” is nothing more than a glorified karate movie, but compare it to the typical karate movie and there’s a world of difference because we care about the characters in “Kill Bill” but we don’t care about the characters in the typical karate movie because they’re so one-dimensional and simplistic.
The basic story of “Rocky” has been told through several sequels, yet each sequel is unique. Recycle the story and you have “The Karate Kid.” Just because “The Karate Kid” is basically the same as “Rocky” doesn’t detract from our enjoyment of it. It’s still a good movie because it has characters we care about and a story that’s interesting.
Be original with the details, but don’t worry about being original with the overall story because you probably can’t. One easy way to come up with the plot for your screenplay is to find a movie that’s similar to your own and model your screenplay after this movie.
“Pulp Fiction” heavily borrows from the film noir genre while “Kill Bill” freely borrows from the martial arts genre. Yet look at the difference between those two movies and the typical mediocre movie in that same genre.
What you want to create is a movie with style, originality, and interest whether it’s a story we’ve seen before or not. Your audience just wants a good story and if they can hear the same story told in a different way like “Finding Nemo” or “The Day After Tomorrow” or “Rocky” and “The Karate Kid,” they’ll still enjoy your movie just as long as you wrote a decent script in the first place.