One million years ago, the Dark Comet accidentally landed on a newborn Equestria. King Mundus and Queen Stella, the Divine Duo, sacrificed Their life force to create the Elements of Harmony to one day combat the malevolent energies of the Comet.

On Twilight Sparkle's coronation day, everything is perfect. Her friends have been with her through thick and thin, and she believes there is nothing friendship cannot overcome. But when the Darkness finally takes a physical form after all these years, the Elements are not enough. Now the Mane Six must conquer a twisted world that is ruled by Vice, representing everything they stand against. Can the heroes become one with their Elements in time to save Equestria from the root of all its problems?