Freed once again from his stone prison, Discord takes on a different approach to getting his revenge; by recanting his past with Celestia and Luna both to the Elements of Harmony.

As Discord tries his best to corrupt the ponies' faith in their seemingly flawless princess and her damaged sister by telling them the whole truth, Discord finds himself second-guessing his position in the rivalry. But what is it that caused Discord to flip the lid in the first place?