After years among the three pony tribes the Two Sisters fight their first great foe by themselves: King Sombra, the tyrant King of the Crystal Empire. Nothing goes as planned, everything, and everypony are not as they seem.
Onyx is a young crystal pony with a twisted mind. Starswirl the Bearded whisked him away from his home with promises of being his apprentice. Sombra is a strange creature who never wanted to be remembered. However, we don't always get what we want...