So you've decided to write a new screenplay. Or maybe a new television or web series. Good for you!
It's time to get your god on...for you are about to become the creator of your own universe. (I wonder if this is how our world started; maybe we're a reality show for some creatures in a galaxy far, far away.)
Once you've decided to create this new world, you need to define it. To the smallest detail. And then make certain your characters reside within this reality, uh, religiously. We'll buy the world you sell us, if you set it up properly. But show us a slip, and we're out of the moment, pulled from the story like Richard Collier (played by Christopher Reeve) in Somewhere in Time when he sees a coin minted from his own time period. And you risk never getting us back again.
Sure, we humans can't [yet] teleport. But when we watch Star Trek, we buy that they do. And Buffy? She rocks! We're willing to roll with her, as we plunge into her unique and fun alternate reality.
So how do you define the rules? Start with the basic definitions first: where are you? What time period is this? Are there any super powers? If so, who has them? Why? If other characters don't seem to notice the paranormal the way the brothers do in "Supernatural," why is that? Define every last detail as you create a Show Bible for your story. And stick to it. Or at least edit back to it in subsequent drafts.
Even as I write my own alternate universes I envy you yours; nearly nothing's sweeter than creating your own rules. While you should have fun in this process, you should also keep in mind that part of the success of a well-crafted alternate reality is that we don't notice it...as we watch your characters and engage in their lives and their stories.
What are you waiting for? You have a universe to create. And seven days may be too long before your next deadline!