It has been nearly two hundred years since the megaspells rained fire down on the world, reducing it to a tainted wasteland. And ever since that day, the changelings have never been sighted in the wasteland...
At Discord's urging, Princess Twilight hops on through the mirror portal to Canterlot High, which had been closed for two millenia. Instead of a school, she finds herself in a cargo bay of a starship. Discord also has popcorn at the ready.
The ES Harmony, the pride of Princess Twilight Sparkle and Equestria's first FTL capable starship. It is due to make its maiden voyage to travel further than anypony before it, and yet its first mission... may be its last.