The banishing of Nightmare Moon has brought much suffering to thestrals throughout Equestria. They are seen as servants to a wicked manifestation of the night, and are treated accordingly. Many officials, including the mayor of Manehattan, use every opportunity to gain from this abuse.
Yet the spirit of the bat-winged ponies is not so easily broken. Count Shadow Wing leads a band of Thestrals to demand their rights be returned... or else.