King Sombra has an heir who is less than thrilled to be his successor. He falls for the daughter of an electrician and finds himself in a conflict. Like his father, he has an insatiable need to enslave and take over Equestria, but a certain filly and her brother stand to stop him. Will Sombra's heir be the second coming of The Dark Crystal Empire or will Diamond and her brother manage to save all of pony society?