What does it take to rule Equestria? Following an argument, Celestia has abdicated the throne and vanished from the memory of Equestria’s citizens, leaving Luna the chance to learn for herself. Twilight, one of the few that still remembers Celestia, has grave concerns about Luna's leadership capabilities. The nobles are restless and foreign enemies circle like sharks, sensing weakness. Meanwhile, far off in the frozen north, Sombra stirs, dreaming of himself on the throne.