One more question that helps you figure out if you’re onto a “monster” idea instead of just a goodish one is, “Is it novel?” That’s what Stefan Mumaw says in his book, “Chasing the Monster Idea.”
Of course nothing is totally new. Even the Bible says there’s nothing new under the sun, and that was quite a while ago.
Generally creativity means the combination of existing elements to produce something different from either of them (and, ideally, more useful or interesting than either of them alone).
Coming up with a new story for a film is especially challenging, given how many films and TV shows and plays there have been.
The good news is that you don’t need to come up with something hugely different–to a degree, people like seeing the same kind of story but they do want some kind of twist. Here are some options:
Gender switch — prime example is “Alien” in which the Sigourney Weaver’s part was written for a man. It made her one of the first female “tough guys.” That switch has been done a lot since, but maybe you can think of an interesting way to have a male in a traditionally female role.
Unusual location – this worked for “Witness,” which took place in an Amish community.
Different time – detective story set in Rome, for instance or in medieval times (“Name of the Rose”)
Different genre or format – “Who Killed Roger Rabbit” mixed comedy with a hard-boiled detective plot and added in the mix of live action and animation for good measure.
What switch might make your story stand out?