The first story of the Memoriis Praeteritum (Memories Past) series

After bunking down for the night to escape the rain, Dark and Simile, two explorers, get chased through a den of Diamond Dogs into some sort of magic dead-end, with an overly-cliched portal resting within.

Weighing choices leaves running through the unknown portal the better option, and Dark, a human barely out of his teens, and Simile, a mare with connections to royalty, find a world completely like the one they knew so well:

Equestria.

Just in time, in fact, for some very weird things to start happening, and it seems only Dark and Simile can do anything about it. And they have secrets of their own to protect.

Oh, sorry, I forgot to mention my name from the beginning.
I am Dark Warrior Scribing, and this is how I came explore Equestria, a world I had assumed to be fictional. Boy was I wrong...