After many happiness, friend making, and also being a hopeless romantic pony dreaming for love, Princess Luna decides to take a break from her princess duties and head to the moon to teach Fluttershy how to get along with her moon creatures. Meanwhile, Luna is informed that King Sombra has returned and is able to get in to the minds and thoughts of ponies. Now it's up to Luna to stop him before the nightmare forces come back and keep the ponies in their nightmares forever.