After Goku defeated the Shadow Dragons, Shenron appears to inform the gang that the Earth must be parted from the dragonballs so as to prevent the reemergence of the Shadow Dragons. Goku, as the happy-go-lucky adventure-seeker he is, decides to join the dragon on its last voyage seeing as the Earth is safe in Vegeta's capable hands. What Goku doesn't know however is that not only is he leaving the planet, he's leaving the entire universe to a new world where the dragonballs would be treated as they were meant to, a thing of extraordinary magic and power: something to be revered. And that world is Equestria.