God created the Heavens and the Earth...as well as Equusterra, the planet of the ponies. Why He bothered to create a whole planet of sentient equines is any angel's guess, but like ponies don't question Celestia, the angels don't question Him either.
When a mishap occurs in the "Heavenly Order of Eternal Reality Systems," the task of going down to Equestria, Equusterra and remedying the situation falls to a human spirit just returning from a relatively short life on Earth. A human spirit that just so happened to have been a fan of a certain television show about the very same colorful ponies.
Old evils will rise, "new" evils will be fought, and Herald the Angel becomes his own real life self-insert in a compilation of seemingly every bad, mary-sue filled fanfic ever written.
Earn your wings and curse the heavens as Equestria's "Holy War" begins.
***RELIGIOUS DISCLAIMER***
This is just a silly little story, as well as my first. This has no intention whatsoever of offending or altering anyone's beliefs or lack thereof. Just have fun with it.