The story follows the fantastic adventures of Phantasmion, king of the imaginary realm of Palmland, as he tries to acquire as his queen the island Princess Iarine and to protect his kingdom from invasion by the mighty conqueror Glandreth of neighboring Rockland. One of his difficulties is that his fertile, agricultural kingdom of Palmland has no metal for armor and weapons, whereas Rockland is rich in metals and its people skilled in manufacturing. He is opposed not only by human enemies but also by malevolent spirits, such as Seshelma, “the fishy woman” who lives in the sea, and Melledine, who can induce sleep and derange the senses.
Phantasmion has only his own courage and ideals and the aid of his guardian spirit Potentilla, the fairy queen of the insects, who provides him with wings and other insect attributes appropriate for his different encounters. Phantasmion has many trials: He is imprisoned, detained in a cave, and rendered insensible by both magic potions and beatings. He often is deceived by the spells and disguises of evil spirits. The magic silver pitcher that bestows on its possessor the love of Iarine continually eludes him and remains in the hands of his enemies.
Phantasmion’s perseverance begins to prevail. He finds human allies in Penselimer, king of Almaterra, and Ulander, chieftain of Nemorosa. Three spirits—Valhorga, the god of the underworld, Feyeldeen, the fairy queen of flowers, and Oloola, goddess of the storm—switch their allegiance to his side. Phantasmion also finds iron mines in Gemmaura, a neighboring province under his control. Phantasmion’s enemies are vanquished, the rightful rulers are placed on the thrones of all the neighboring kingdoms and unite in peace with Palmland, and three weddings bring happiness to the worthiest of the young people, especially Phantasmion, who at last acquires the silver pitcher and the hand of Iarine.