Mammoths. A species that was supposed to be extinct for more than a millennia.
At least, that's what every pony believed.

But now, after a thousand years of isolation, the Mammoths have returned!

By accident, these great beasts stumble across our heroes in the town of Ponyville and turn their worlds upside down! Soon, they learn that the Mammoths are making an epic migration towards their old grazing lands in the Crystal Empire. Now, Twilight and her friends must embark on a dangerous quest to help their new-found allies reach their ultimate destination. Along the way, they face off against ruthless foes and form a close bond with these long forgotten creatures.

This story takes place after the events of the "Crystal Empire" episodes.