It all began with changelings—mysterious creatures from the Badlands who could shapeshift into anything and anyone.
When they took over Canterlot, they shocked many not with the swiftness of their attack but with how many in Equestrian society had been replaced long ago with changelings, their true identities revealed when it was too late.
In the year or so that followed, Equestria pulled back full tilt, desperate for a safe place to hide. However, no matter how the ponies tried to conceal themselves from their foes, they would always succumb to the changelings—whether by brute force from without or by covert infiltration from within.
And now, the most formidable outpost of the resistance against Changeling Queen Chrysalis—Camp Ponyville—was reported fallen, vanquished by an iron hoof. To those still alive, the changeling armies became only more unstoppable than ever before, shaking Equestria to the very core.
Or, rather, what's left of Equestria.
With this piece of news, everyone on all sides were left thinking about their next steps.