You are Anonymous, the only human in Equestria. (Yeah, it's one of -those- fics.)
The previous week has been a nightmare for you. Why? You broke a Pinkie Promise, and the party pony made you pay for it. A whole week at her command, but you couldn't keep up. This, of course, has left you with a fear of breaking any other Pinkie Promise ever again.
There's a problem though, you have one promise left to fulfill before you can stop worrying about breaking another. During your "sentence", Scootaloo lent you a hoof with a few things. Being immensely grateful, you promised her one favor. How can a favor to a little filly be so bad? You told her that the favor could be anything her little heart desires of you. Anything.
What will her favor be? You can only hope it won't be anything serious.