Rainbow Dash have faced many threats together. Nightmare Moon. The Bad Apples. Grand Heist. Hang Ém High. Discord. The Shadowbolts. King Sombra. The Changelings. Captain Squirk and his pirates. THe Parasprites.

Now familiar faces from the past return to the present as the six mares (and dragon) must face the greatest challenge yet: The Corruptions of Ruin. WIll they be able to face powers made to counter their own skills and ideals?

And on the eve of the return of the greatest mage in Equestria too...