There are no original plots so don’t waste time trying to create an original plot. Instead, focus on creating an original story based on an unoriginal plot. One simple way to create a plot is to simply “borrow” a plot from another story.
“Clueless” was actually based on Jane Austen’s novel “Emma” except modernized for today’s world. The Korean comedy action thriller “The Good, the Bad, the Weird” was based on “The Good, the Bad, and the Ugly.”
Take a familiar plot from one story and put it in a different time period such as what “Clueless” did with the novel “Emma.” Take a common plot like one man against an army of villains and change the setting. “Die Hard” put the hero trapped in a skyscraper, “Under Siege” put the hero trapped on a battleship, and “Speed” put the hero inside a speeding bus.
The real creativity in story telling never comes from the plot but from the way the plot unfolds with characters unique to your particular story. Although “Die Hard” and “Under Siege” are basically the same story, the different settings make each story unique.
If you’ve ever watched a bad movie, borrow the plot and use it to write a good screenplay. Don’t worry about creating original plots. Worry about creating original characters in original settings who behave in original ways. The real creativity in screenwriting always lies in character development and story structure, not in the plot.
“Cinderella” is about an underdog trying to survive in a harsh world, which is no different than “Rocky” or “The Karate Kid.” “The Bad News Bears” is about an underdog baseball team, which is nearly identical to the underdog running team in “McFarland.” There are few original plots so don’t bother trying to find one. Focus on telling interesting scenes with original dialogue to support a compelling story. If you can do that, everyone will forget that they’ve seen the same plot before.