Far from Canterlot and forced to work in gem mines for cruel Diamond Dogs, a young unicorn named Bone Marrow's pursuit of his cutiemark reveals a unique talent: raising the dead.
Anyone who has sought counsel from Princess Celestia has met Raven, her most faithful aide. She has been a veritable second shadow to the princess for as long as the castle staff can remember... longer than they can remember, in fact. Much longer.