Rumors of a certain creature which is called, "dream demon" has been spreading around Equestria for quite a while. It's origins seems to be from a planet which is named Earth. They are said to posses powers that are similar to Nightmare Moon.

One day, the main demon haunts Equestria, and causes havoc.

There is a secret prophecy that was lost for 500 years, which tells of dream demon who comes once every 500 years and can only be defeated through a matter of 7 ways. If the demon is defeated in 6 of those ways, then for 500 years there will be peace. Can Twilight save Equestria from the dream demon? There is only one way to find out.