When Carlin and Loraine Restoney are invited by their grandmother to move to the Kingdom of Pespermeir to become heirs to their mysterious Uncle Casper, they don't know what to say. Despite warnings and rumors, the curious siblings soon discover the truth: their uncle is the caretaker of the mythical fethilars, flying horses long thought extinct. Around the same time, under mounting pressure of too many knights, the 5 kings announce a special tournament, to resettle the wild and untameable land of Arbocath. But Arbocath has dark secrets of it's own, which only the fethilars know how to cure. Loraine and Carlin soon find themselves fighting bandits, tending unicorns, dodging dragons, trolls, and a host of other monsters, all to care for and protect the very pregnant fethilar mare Moonbat. In addition they have to attempt the monumental task of stopping the king's tournament while their uncle is away. All the while, the foreboding Ebony Hearthrug and Swamps of Shandell silently wait...