Rand kicks things off with dread and doom. The world is in serious trouble: the economy is tanking, and the government is becoming crazy-oppressive. But fear not: we meet two heroic businesspeople who might just be savvy enough to keep the country going. Hank Rearden and Dagny Taggart team up on a major mission: to build a railroad to provide all the up-and-coming businesses in Colorado with transportation for their merchandise. Hank and Dagny succeed, with the help of some other good businesspeople, and the John Galt Line, which uses a special metal that Hank invented, is a success.
Who is John Galt? Well, the whole world is wondering that. While all this is going on, more and more talented people are mysteriously disappearing, and John Galt may just have something to do with it. But Hank and Dagny are more concerned with other things now. The two begin a romantic relationship and a new quest: to find the inventor of an abandoned high-tech motor that could transform the world. The search leads them all over the country, where they are increasingly confronted with evidence of the bad economy and government.
Things begin going rapidly downhill for Hank and Dagny. The government, a sleazy crowd of politicians and businesspeople (including Dagny's weasel of a brother James), passes a series of laws that restrict people's freedoms. These laws particularly target successful industrialists and make business, and life, hard and miserable. More and more industrialists disappear and Dagny becomes obsessed with tracking down the "destroyer" of the world.
Hank, meanwhile, is coming to some painful personal realizations about his family life and his morals. He is being helped along by the mysterious Francisco d'Anconia, a supposed playboy who used to date Dagny and is somehow connected to the "destroyer." Dagny sets off on a desperate solo quest to stop a scientist from quitting his job and disappearing. While following the scientist, Dagny crashes her plane in Colorado.
When she wakes up, she finds herself in the secret hideaway of none other than John Galt and his fellow strikers. This valley is often referred to as Galt's Gulch by the strikers, though Dagny calls it Atlantis. Galt is both the inventor of the motor and the "destroyer," and he's calling talented people together to go on strike in order to show the government how harmful their policies are. Galt and his followers refuse to cooperate with an oppressive regime, which they call the "looters."
Galt has been in love with Dagny for years, and she quickly falls for him too. But Dagny can't bring herself to stay on strike in Galt's Gulch, since she still feels she can fight the terrible government. Dagny returns home and has an amicable breakup with Hank, who shortly thereafter joins the strike and leaves for Atlantis.
After things in the world become even worse, Galt makes a long radio address, outlining his philosophy and asking people to stop going along with the bad government policies. But Galt is captured by the government shortly thereafter and is tortured. Dagny, helped by Hank, Francisco, and other strikers, rescues Galt, and the group flees for Atlantis as the country's infrastructure collapses. At the very end, Galt and his strikers make plans to return to the world and to fix it.