Sunset Shimmer receives remarkable news: Princess Twilight's becoming the queen of all Equestria! But as her friends celebrate, Sunset struggles with her own destiny when dangerous, new magic leaks through a rip in space-time above Canterlot High.
Spike woke up to find himself as his pony caretaker, Twilight Sparkle, while the original Spike somehow still acted like Spike himself. The now-pony decided to go about fixing it alone, with both expected and unexpected results.
A dragon assistant toiling away in the Castle of Friendship suddenly found himself as a familiar unicorn fashionista. What's more, he was shocked to find himself stranded in a critical moment of the not-so-distant past.
An unwilling non-brony traveller from Earth finds himself switching between bodies of the Ponyville locals randomly, leaving so much chaos and confusion in his wake that Discord might as well retire now.
I woke up as Lyra Heartstrings. I managed to become a pony, but I don't know how. I somehow unwillingly also managed to get in the way of Equestria's fate.
Princess Celestia and Pinkie Pie have a Freaky Friday Flip and Twilight and her friends must restore them before a thousand year old acquaintance of Luna turns her back into Nightmare Moon and bring back eternal night.
Lyra thinks Discord is an idiot for not thinking to dodge when the Elements of Harmony were about to strike him. Discord thinks this is the perfect opportunity for a game.