Luna has a fear of losing control, so it doesn't sit well with her when the land of Equestira is under siege again this time by a nightmare from the dream realm and the only one with the ability to save it is her.
She will learn the truth about her power and how to control it and she must do it fast before all of Equestria is under the nightmare spell. Black the Dream Gate keeper comes to Equestria in an attempt to fix what has happened.