(Submission for the Sci-Fi contest)
Research into parallel universes has proven to be a limited success. But what happens if the greatest wizard in Equestrian History with access to such a spell runs head-long into one of the greatest threats a newly-formed Equestria might ever face? Will the researcher approve? Will the Princesses? Will History?

(Extra-cartoon locations are also derived from "Map of Equestria... And Beyond!" by "KeenKris" on DeviantArt)