The Doctor, a Time Pony, leaves his home-world, Gallopfrey, because, quote, "It's really quite rubbish." He finds a world called Equestria, which is more than a bit strange. For one thing, it's a geocentric system rather than a heliocentric one. He decides to investigate, but finds his query cut short by a visit from some old foes, the Cyberponies. Joined by the wall-eyed Derpy, the psychedelic songstress Vinyl and the refined Octavia, the Doctor must find a way to save his new friends and all of Equestria.