Despite the warnings of his father, the great white Unicorn, Blackie ventures from his secure refuge in the heart of the forest into the restless, striving world of humans. His travels take him from the peaceful Shrine at the top of the world to the burning dragon pit at its bottom. Blackie meets monsters and beasts and humans of every rank from beggars, gypsies, peasants, and priests to knights, nobles, and his irrepressible, irresistible Princess. He learns the joys of love, friendship, and a well-baked bowl of cookies, as well as the miseries of sickness, treachery, and death. Ultimately, he learns what it means to be unicorn, a "holy beast" to the humans with his celebrated horn of violence in battle and healing in sickness.