After stopping the apocalypse Taylor Hebert is shot in the head. However, a mysterious force grateful for her actions in saving the world saves her and subsequently transports her to Equestria, transforming her into a Changeling Queen.
The Chosen Undead is on the verge of undoing the curse of undeath cast upon humanity by Lord Gwyn, when he falls for a trap laid within the First Flame and is transported to Equestria, over a thousand years in the past.
Who is Nightmare Moon without Luna? Without the drive to bring eternal night, her jealousy at her sister? Without Luna's influence could there be a chance for the Nightmare to be redeemed? In this Universe Equestria about to find out the answers.
The princesses gave their magic to Twilight to prevent Tirek from stealing it. As a result, they end up stuck in Tartarus. The fact that things manage to go downhill here says a lot about the wonders of family.
Twilight learns of Sombra's past, and finds him alive but weakened. She decides to learn how to use his Dark Magic for Good, by taking him back to Ponyville.