It's a bright spring day in Ponyville, and Twilight Sparkle is exactly where you'd expect her to be. In the library, that is. Specifically, she's hunting for where she mislaid Principles of Proto-Equestrian Orthography because she just can't read Starswirl's hornwriting without it. Hmm, maybe Spike put it back in the storage room—
a horse walks into a bar
deep-in-dreams
They will all find themselves, then, apparently in the throne room in Canterlot, in the presence of a certain alicorn princess with power over dreams.