(Only the back-story is dark, so I'm not going to put the tag, unless asked to do so. OC characters included)
As Rarity and Spike search for some more jewels for one of the fashionista's FABULOUS dresses, Spike comes across a particular jewel that sends him and Rarity to another version of Equestria.
In this world, two tyrants that came from yet another dimension, have conquered most of the planet, and their armies of demons and monsters ensure that any land taken from each other is shared through blood and death.
This has lasted for five-hundred years, but, the two alicorn princesses are nowhere to be seen...somewhat. However, Spike and Rarity don't end up in that scenario right away. No. Rather, they end up in tunnels underneath the whole events of the world, and Rarity will discover something that could change the events that have lasted for over five centuries. More-so, they discover the new situation of many of their former friends and enemies and how they are coping with this new world...or what has befallen them upon this new world.
Rarity and Spike are the only hope left for this Equestria, but what chance does a fashion designer and a baby dragon have in defeating the tyrants where powerful armies and alicorns have failed?