Twilight receives an ancient book of Equestrian myths from Princess Celestia with the warning that all of the myths contain some degree of truth. And she begins to read
After a deadly attack of seemingly unknown origins, Luna and Celestia begin talks of reviving an ancient order meant to defend Equestria and the rest of the known world from threats deemed 'other worldly'.
A forty-one-year-old Twilight Sparkle causes a chain reaction of temporal problems when she travels through time as her last hope for answering her vast questions about who she is and where she belongs in the universe.
Ever since Twilight became an Alicorn, a bunch of strange new ponies have been appearing and Twilight and her friends don't know what to make of them. Hopefully, these new ponies will be willing enough to make friends with them.