The headstrong Princess Ernalie is one day carried off from her kingdom by an eagle. Unable to return home because of impassable terrain, she settles into her new home with the former king and queen of the land, who have been dethroned. She then discovers that a feather from the tail of the eagle who carried her off gives her the power of invisibility. When she gets to know the king and queen's son Treblo, love spurs her on to undertake a voyage to the moon in order to save his life. During this adventure, which she carries out with the help of the feather, she makes the acquaintance of no less than the Man in the Moon, the Fates, and the goddess Diana. But her flight home from the moon lands her back in her original homeland, divided from Treblo by impossibly hostile terrain. Can she find a way to reunite with him? (Summary by Scarbo)