The Cutie map send Starlight Glimmer to help the royal Sisters and stop their arguments. In a quick flash of panic, she switches their cutie marks. Unknown to her a darkness's rises in the dreamscape. In her dream, She see's Nightmare moon and a darker version of Celestia, Daybreaker, fight each other. then Celestia and Luna appear. Surely Celestia can defeat both of them with the support of her sister?
Wrong.
Celestia can't help but to give to the darkness in her heart. Which allows these dream demons to be free to take over..... their bodies.
Starlight now awakes to a new world were it i both day and night.... A total Eclipse.