(Spoilers for those who still haven't seen My Little Pony: A New Generation yet. Featured from 11/09/21 to 11/10/21.)
Sunny Starscout and her friends have managed to restore magic to Equestria by getting the three pony tribes to unite again. It seems like all is right with the world as far as most ponies are concerned.
But Sunny still wonders what could've caused the bright future Princess Twilight Sparkle had planned for Equestria to fall apart, and how the ponies could've grown to fear and hate each other. And her search for answers yields an unusual result in the form of Princess Twilight herself.
Being brought into an Equestria so different from her own, Twilight is confronted with a horrifying fact: Her legacy has been tainted, defined by the collapse of harmony between ponies after her time. And Sunny will soon learn just what it is that Princess Twilight was trying to do to keep the ponies together.