Twilight and her five friends are transported during a botched spell, across dimensions to... Ponyville, Equestria? But not the same one that they knew. Sitting on a bench is Harpsy and Babar. The Doctoress avoids apples from an aspiring Applebuck. And in a library across town, six stallions join their forces as they try to decipher the appearance of filly look-alikes of themselves around Ponyville!

Mood Wings - Observations on Pegasus Body Language.

When Twilight Sparkle finds this book, she discovers an entirely new field of research. The secrets of pegasus wings lie before her, and she insists on making her own observations on the matter.

How?

Field research, of course.

A short trip to Canterlot with Rainbow Dash and Applejack is the perfect opportunity for Twilight to test out her new long-distance Teleportation spell. But a nasty cold dashes the hopes of a quick trip, and makes the spell disappear in smoke: instead of arriving in Canterlot, the three find themselves in the nearby Everfree Forest, and discover that their location is not the only thing that went wrong.

While Rainbow has exchanged her wings and tail for a straw blond tail, Applejack has acquired a rainbow tail as well as a pair of strong, blue wings.

While Twilight attempts to find a spell to return the body parts to their rightful owners, the others must attempt to deal with this situation... and with their changing feelings.