Every story fits into a specific genre such as horror, mystery, or action. The genre of your story defines its unity. How you tell that story must be different than anything people have seen before so that defines the variety.
That means your story must embrace both unity and variety. Unity means your story meets a genre’s expectations. For example, most horror stories involve a hero (usually female) trapped in an isolated area against a relentless villain trying to kill her.
If you’re going to write a horror story, stay within the expectations of the horror genre unless you have a specific reason to break this rule. The expectations of the horror genre work like this for various movies:
- Hero (Ripley, female officer)
- Isolated area (a freighter starship way out in the middle of space)
- Relentless villain (Alien creature)
“Ready or Not”
- Hero (wedding bride)
- Isolated area (in a mansion and the surrounding land)
- Relentless villain (in-laws trying to kill her)
- Hero (young woman)
- Isolated area (trapped inside a boarded up house)
- Relentless villain (a blind killer)
Notice that each story fits within the expectations of the horror genre (unity) but uses a different hero, setting, and villain (variety). As a general rule, switch one feature of a genre at the most because if you switch too much, you’re no longer in the genre.
“Jaws” replaces a female hero with a male hero (the sheriff) but keeps the isolated area (a little boat in the middle of the ocean) and a relentless villain (a great white shark).
“It Follows” keeps the female hero but eliminates the isolated area. Instead, the hero is free to go anywhere she wants. The problem is that everywhere she goes, the villain (a ghost) will appear and shuffle towards her to attack her.
So although the hero in “It Follows” isn’t isolated, she can’t get away from the villain because no matter where she goes, the villain will be there.
When writing your own story, focus on unity first by making sure you meet the expectations of your chosen genre. Then within that genre, look for variety to offer something different.
By combining unity with variety, you can offer audiences the same thing, only different.