Story Starters for the aspiring Fantasist!

Here is a quick little writing exercise taken from The 29 Most Common Writing Mistakes (And How to Avoid Them) by Judy Delton. It's a creativity exercise meant to help you get writing when writer's block has set in. Based on the title and first sentence below, start a story. It's just that simple.

Story Starter

Title : In The Dark
First Sentence : I was waiting for a letter when...

And, if you don't like the title listed above,
Here is your title:
The Black Molecule Who Multiplied