The Changelings were defeated, and so Canterlot was saved... or so the populace was led to believe, anyways. Unfortunately for Equestria, their assailant was prepared - and even a loss at the hooves of her greatest foe served her plans.

Queen Chrysalis's strategems were meticulously prepared, yes. But in all her scheming, all her machinations, there was one small oversight, something her plans never accounted for...