It has been five years since Princess Nightmare Moon overthrew her sister and cast Equestria into eternal night. During that time, her son, Prince Skipting Lunam, has proved himself time and time again to be her most loyal subject. The Elements of Harmony are no more. Rainbow Dash, the former Element of Loyalty, swore an oath to Princess Nightmare Moon, and became one of her most loyal and skilled knights. Rarity Belle, the former Element of Generosity, has become a maid and seamstress in the castle. The other four, however, still reside in the small village of Ponyville, including the Princess of Friendship, Twilight Sparkle.

Princess Nightmare Moon has asked Prince Skipting Lunam to go through the mirror portal within Princess Twilight’s castle, to go to the alternate world on the other side of the portal, in order to help a girl named Sunset Shimmer, the daughter and former personal pupil of Princess Nightmare Moon’s older sister, Celestia. Someone at Sunset’s school has created an online account, known as "Anon-A-Miss'', that has been spreading the secrets of students, which led to many students turning against her, even her friends.

Skipting will do whatever it takes to protect Sunset, but when old family secrets start coming back to haunt them, it may cause a rift between parent and child.