After a failed attempt to climb K2, the world’s second-highest mountain, Greg Mortenson is lost in the mountainous Karakoram region of Pakistan. Eventually, he wanders into the remote village of Korphe, where he receives help from the people and meets the village chief, Haji Ali. After Mortenson sees some children trying to study by writing in the dirt with sticks, without even a teacher to instruct them, Mortenson promises to return to Korphe one day and repay their kindness to him by building a school. Back in the U.S., Mortenson returns to his job as a trauma nurse in California. He keeps his belongings in a storage building and lives in a car he inherited from his grandmother. He reflects on his early life in Tanzania, where his father was building a hospital and his mother was starting a school. He also remembers his developmentally disabled sister, Christa. After her death the previous year, Mortenson had undertaken the K2 climb to honor her memory, but he now realizes that the Korphe School would be a more fitting memorial.

Mortenson knows little about fund-raising, and although he sends out 580 letters requesting donations, he receives only one small contribution. After an acquaintance writes about his project in a mountaineering journal, Mortenson receives $12,000 from Jean Hoerni, a wealthy physicist who is also a climber. Mortenson sells all his belongings to pay his own expenses, returns to Pakistan, and purchases building materials for the school. In the process, he acquires a sympathetic guide, learns about bargaining practices in the region, and gets two of the traditional outfits worn in Pakistan. He believes his mission is almost accomplished, but when he returns to Korphe, the villagers explain that he must first build a bridge across the deep river gorge that separates Korphe from neighboring areas. Mortenson realizes that he has not planned well, and after promising to come back and build the bridge, he goes back to America discouraged. There he finds he has lost both his girlfriend and his job.

Mortenson is depressed for a time, but he finally contacts Hoerni again and receives additional money for the bridge. Back in Pakistan, he continues to develop his relationship with the local people, goes on a hunting expedition with the men of Korphe, and completes the bridge. This time he returns to California with a feeling of success. He is invited to attend a dinner honoring Sir Edmund Hillary, the first man to climb Mt. Everest. At the dinner, Mortenson learns that Hoerni and his friend George McCown will pay Mortenson a salary while he completes the Korphe school. Mortenson also meets Tara Bishop, the daughter of a noted photographer and climber. The two are instantly attracted to one another and marry a few days later. Mortenson returns to Pakistan and completes construction of the school. He also learns more about local customs from Haji Ali, who encourages Mortenson to respect the ways of the Balti people.

Mortenson begins to look for the next place to build a school. He travels alone to Waziristan, where he is kidnapped and held for eight days without ever knowing why he was captured or released. When Mortenson returns to the U.S., Tara goes into labor and has a daughter. Not long after, Jean Hoerni, just before his death, endows the CAI $1 million and names Mortenson the director. In the following months, Mortenson continues his work and builds several new schools. A conservative Pakistani cleric issues a religious indictment against Mortenson, but through the efforts of Ghulam Parvi, who manages CAI affairs in Pakistan, and the moderate cleric Syed Abbas, the fatwa is lifted. Mortenson and the CAI continue to develop a school-building program focused on the education of girls, and they also begin to help refugees and to provide eye surgery and other medical care in the region.

During the periods he spends in America, Mortenson tries to raise funds for the CAI and attempts unsuccessfully to raise awareness about conditions among refugees. Mortenson’s difficulties with organization and communication begin to strain his relations with the CAI board, and he goes through a period of depression. His sprits improve, however, when Tara gives birth to their son, and Mortenson returns to Pakistan with a more professional approach and a renewed sense of mission. He realizes that political conditions are worsening in Pakistan and Afghanistan, in part due to efforts by ultra-conservative Muslim groups to build their own schools, called madrassas. These schools offer free education to boys, but often use the opportunity to enlist the students in militant activities. On September 11, 2001, while Mortenson is dedicating a school in Pakistan, the terrorist attack on the World Trade Center and Pentagon takes place. Mortenson speaks out to reporters and explains that terrorism is rooted in poverty and lack of opportunity, but his message receives little attention.

Another fatwa is declared against Mortenson in Pakistan, and at home he receives hate mail from Americans who condemn his efforts to help Muslims. He is also interrogated by the CIA. He does, however, win the support of Representative Mary Bono and is invited to talk to several congressmen about his work. Finally, a reporter who has traveled with Mortenson writes a cover story on his work for Parade Magazine, and the CAI receives a large number of donations. Mortenson’s work gains national attention, and the book ends with his decision to expand the CAI’s work into Afghanistan.