Sometime in the Dark Ages, the aged Saint Maël of Ireland finds a miraculous ship made out of stone on the coastline near his monastery. The venerable saint takes this as a sign from God that he should travel the world spreading the Word of God to all the pagans and heathens. After some considerable initial successes, the Devil becomes understandably irritated with St. Maël, and decides to end his progress. The Devil tricks St. Maël into setting out to sea once again, and then sends demons to create a tempest to blow him thousands of miles southward.

When the storm subsides, St. Maël, half blind and deaf from the salt water in his eyes and the crashing of the waves in his ears, finds himself on what first seems to be a deserted island. However, he eventually finds a crowd of what appear to be short, stout, black men, assembled in an amphitheater. Mistaking them for a great senate, he begins to evangelize to them. St. Maël tells them of the Gospel and, as his audience seemed to be rapt in their attention to him, he proceeds to baptize them.

However, what appeared to be a peculiar race of very short men was, in fact, a large number of penguins, who, fascinated by the sight of a creature the likes of which they'd never seen, had flocked to St. Maël's side. The baptism of these penguins understandably caused quite a stir in Heaven; after all, one is not supposed to baptize penguins. God Himself was embarrassed by this turn of events. Although the sensible thing to do probably would have been to declare the baptism null and void, this offended the sensibilities of God and the assembled saints, who all decided that the "magic" in baptism applied to animals and inanimate objects. Therefore, the penguins would have to be given immortal souls. Furthermore, since penguins live in a state of nature, and not in a state of grace, they would all go to Hell if they were left as they were. Thus, the heavenly host decided to transform the penguins into men. That being settled, St. Maël attached the island to his stone ship and sailed with in northward, eventually anchoring it somewhere in the general region of Europe.

Having described the origin of the Isle of Penguinia and its inhabitants, France goes on to parody the beginnings of monarchy on the island, the nature of nobility, the Catholic Church, republicanism, and many other things. The focus of the book is the history of the Penguin nation, from its birth to the present and even into future times. Overall, an exceedingly charming book.