Ella Minnow Pea is an eighteen year-old girl who lives on the small island of Nollop with her parents Gwenette and Amos. Ella's cousin Tassie and Tassie's mother Mittie also live on the island. Nollop is an independent island nation located just of the coast of South Carolina. Its population is diverse and the tight-knit society experiences little or no strife. Nollop was founded on the principle of equality for all shortly before the American Civil War and it remains peaceful, if isolated.

Nollopians prize language and its proper use above all. The people living on Nollop are not fond of modern technology and because of a recent hurricane, telephone service is inconsistent at best. Nollopians as a rule do not use computers with any regularity. There is a university on the island. Most of the inhabitants are avid readers and letter-writers. The love of the written word is instilled in Nollopians from an early age.

In the square in the middle of the town of Nollopton stands a statue of the island's most prominent citizen, Nevin Nollop. To those living on the tiny 63 square-mile land mass, Nollop is a hero. Approximately one hundred years ago, Nevin Nollop wrote a sentence which used every letter of the English language. His pangram, "The quick brown fox jumps over the lazy dog" is proudly displayed for all to see and revere. One day, the tile bearing the letter "Z" falls from the cenotaph and life on the island of Nollop changes forever.

The High Island Council, Nollop's governing body, believes that the falling of the cenotaph tile is a sign. The Council believes that Nevin Nollop is communicating with them from beyond the grave. The members of the Council interpret the falling of the tile to mean that Nollop wishes them to discontinue use of the letter "Z" and they forbid the islanders to ever use "Z" again. Those using the letter "Z" once will be reprimanded, publicly flogged or put in the head-stocks. Some will be banished, others will be put to death if they refuse exile.

Ella Minnow Pea, her family, and neighbors tell the story of what happens on the island of Nollop through a series of letters. Each letter reveals the gradual breakdown of language, communication, and meaning on Nollop. As more tiles fall from the hundred year-old cenotaph, tensions mount, and each day people are punished and banished with alarming swiftness and increasing cruelty. The High Council begins taking over the land and property of those who are exiled and Nevin Nollop becomes their god.

Ella, Tassie, Mittie, and the others are confused and outraged at the happenings on their beloved island. It soon becomes clear that no one individual will be able to stop the High Island Council's figurative march toward linguistic totalitarianism.