This story is a sequel to Equestria Wars Episode XI: Attack of the Vines
A few months later since the defeat of Omega Brony and Twivine, Danny had a vision that Arthas the Lich King and Havoc, Discord's Twin brother have returned to Equestria and has started a war in Equestria. Charming Thunder will be dealing with Arthas while Danny deals with Havoc hoping to resolve the upcoming darkness.