The narrator, Equality 7-2521, begins by remarking that it is a sin to write as he is doing, thinking for oneself and setting down words on paper for oneself alone. The society in which he lives is dystopian, totalitarian, and collectivist, though he believes that he is the one at fault for failing to espouse its values completely. Any kind of individuality is regarded as sinful in this society, and Equality 7-2521 refers to himself in the plural, as “we,” since there is no first-person singular in the language. He tells the reader that he was born with the “curse” of a questioning mind, which has always driven him to think for himself, though he tries to be like other men.

The society in which Equality 7-2521 lives was formed in an event called the Great Rebirth. It is a crime to speak of the times before the Great Rebirth, and knowledge of that time is swiftly passing out of human consciousness. Equality 7-2521 describes his childhood and youth in the Home of the Infants, then in the Home of the Students. He had hoped to finish his education in the Home of the Scholars, but instead the Council of Vocations decreed that he should become a street sweeper. This upset him, and he regards the assignment as a punishment for being unable to control his thoughts.

While sweeping the streets, Equality 7-2521 finds a tunnel dating back to the time before the Great Rebirth. Instead of reporting this discovery, as he is supposed to do, he uses the tunnel as a secret hideaway, studying and conducting scientific experiments there. Another sign of his unorthodox nature is that he has fallen in love, an emotional state which is forbidden and must be kept secret. The woman he loves is called Liberty 5-3000, though Equality 7-2521 thinks of her as “the Golden One,” another transgression. One day, he tells her that he thinks she is beautiful, and she confesses that she is also attracted to him. The encounter makes Equality 7-2521 conspicuously happy, and he is reprimanded for singing at the dinner table.

In the course of his experiments with electricity, Equality 7-2521 invents the light bulb. He decides to present this to the World Council of Scholars, certain that they will reward him for conferring such a benefit upon humanity. However, when he shows the light bulb to the scholars, he finds that they are more concerned with the sins of individualism he committed in developing it than in the utility of the invention itself. When he sees that they intend to punish him harshly, Equality 7-2521 escapes through a window and runs away to the Uncharted Forest. The solitude and peace he experiences in the forest are very attractive to him, and his greatest regret is that he will not be able to see Liberty 5-3000, the Golden One, again.

However, Equality 7-2521 sees the Golden One the next day. She has come to the forest to find him. They kiss, have sex, and wander through the forest together, experiencing a joy which they do not have the vocabulary to express. They have been taught only ever to use the plural, but the phrase “we love you” is clearly awkward when the Golden One uses it. They find a house in the mountains which has clearly been abandoned since the Great Rebirth and contains numerous objects from earlier times. As Equality 7-2521 reads the old manuscripts, he discovers the forbidden word I. He reflects that the happiest moments he has ever known—reading, making scientific discoveries, and being with the Golden One—have all been individual, rather than collective.

Equality 7-2521 concludes that individualism, far from being a sin, is the basis of being and that everything he has been taught is wrong. He chooses a new name which he has learned from his reading: Prometheus, who gave the gift of fire to mankind (paralleling his own attempt to give mankind the light bulb). He decides that the Golden One should be called Gaea. They live together in the old house, learning about the times before the Great Rebirth. Prometheus intends to replicate the achievements of those times, including powering the house with electricity. When Gaea becomes pregnant, Prometheus vows that he will bring his son up to be an individualist and live as men used to live.

Prometheus concludes by reflecting on collectivism as one of the forms of slavery that has plagued humanity throughout history. People have been enslaved by gods and kings and by family and tribal loyalties and, most recently, by a sense of duty to society as a collective whole. He intends to fight against all forms of slavery and champion the rights of the individual, building a new society based on the supreme value of personal freedom. The sacred word which he says will always be his beacon and his banner in this struggle is ego.