Sunset Shimmer always saw herself as the hero of her own story, her pride would settle for nothing less. Such views were challenged after spurning the controlling, demanding influence of her mentor, and finding herself an outcast. But never one to take life's hits without hitting back, she finds her way back to Canterlot Castle and via the relics hidden there, to a galaxy so much larger then she first thought.
Beyond the mirror portal, the colony ship Star Strider and its fleet has proudly wondered the galaxy for aeons, spreading Earth's many children among the stars and life to the barren worlds surrounding them. Planning on taking advantage of her new home, hitchhiking aboard the alien star ship far from Equestria, Sunset sets in motion plans to bringing technological and magical revolution to Equestria, intent on sating her lust for recognition and forwarding her uncertain path to alicorn ascension.
However it seems fate would derail her plans for the second time when she returns to Equestria, only to find it empty and pillaged. It is evident Earthlings are not the only creatures exploring the galaxy, and there are others that covet Equestria's bounty of magic with uncompassionate fever.
But Sunset is no pony who would see her ambitions crumble beneath poor circumstances, and knows that any calamity just another opportunity in disguise. Her victory will not come come through conquest, but with some good old fashioned heroics. After all, she has an unwitting rival to catch up to when it come to saving the world.