This story is a sort-of sequel and expansion on the events portrayed in both Alex Warlorn's 'Dark World' as seen here: Dark World Apple Tree and WandererD's magnificent fanfic The Changeling Queen

I like to think that it's not 100% necessary to read their works to read this one, but it does help. And those stories are very fine pieces of work in their own rights!

My deepest thanks to both authors for allowing me to reference their works.

The Elements of Harmony find themselves facing an old evil united with one from beyond their world entirely, bringing magic so alien that Equestrian magic cannot defend against it.  Yet, long ago, when the Elements existed in a different form, they summoned aid from beyond the world to defeat a similar threat from beyond.  

Out of desperation, today's Elements repeat that ancient summoning, and they get – a hillbilly with a silver-strung guitar?

MLP:FiM (c) Lauren Faust and Hasbro; John the Balladeer and Rowley Thorne (c) estate of Manly Wade Wellman