On August 6, 1945, the American army decimates the city of Hiroshima with a bomb of enormous power; out of a population of 250,000, the bomb kills nearly 100,000 people and injures 100,000 more. In its original edition, Hersey’s Hiroshima traces the lives of six survivors—two doctors, two women, and two religious men—from the moment the bomb drops until a few months later. In 1985, Hersey added a postscript that now forms the book’s fifth chapter. In this chapter, Hersey reexamines these six individuals’ lives in the forty years since the bomb.

The Reverend Mr. Kiyoshi Tanimoto, a community leader and an American-educated Methodist pastor, is uninjured by the explosion. As fires spread around the city, he helps get people to safety at a small park on the outskirts of the city. Tanimoto is aided by Father Wilhelm Kleinsorge, a Jesuit priest. Despite his own illness, Father Kleinsorge consoles the wounded and brings water to those who need it. Many of the victims are too weak or wounded to move, and in the absence of any official help, people like Father Kleinsorge and Mr. Tanimoto are left to protect them from encroaching fires, whirlwinds, and the rising tide of the river. Among the victims they help are Mrs. Hatsuyo Nakamura and her young children.

Miss Toshiko Sasaki is a young clerk whose leg is fractured in the blast. Her wound becomes terribly infected, and she receives no real medical help for weeks after the explosion. The bomb kills more than half the doctors in Hiroshima and injures most of the rest; Dr. Masakazu Fujii, for instance, is unable to help anybody but himself for a long while. Dr. Terufumi Sasaki, on the other hand, remains the only uninjured doctor on the staff of the Red Cross Hospital, and in the months after the explosion he barely leaves his post, trying to stem the tide of death rising around him.

Weeks after the explosion, after Japan capitulates and Hiroshima begins to rebuild, a new terror strikes: radiation sickness. Victims become nauseated, feverish, and anemic; many people, such as Mrs. Nakamura, watch their hair fall out. The disease baffles everyone, and many, including Father Kleinsorge, never fully recover. Still, the people of Hiroshima try to return to their normal lives. In his added postscript, Hersey traces the lives of these six characters in the forty years after the atomic bomb. Father Kleinsorge and Dr. Fujii die from sudden illnesses years later. Mrs. Nakamura and Miss Sasaki scrape their way up from the bottom to become happy and successful. After working hard and supporting her family, Mrs. Nakamura lives comfortably on a pension and a government allowance, and Miss Sasaki becomes a nun. Dr. Sasaki and Mr. Tanimoto devote their lives to helping people. Mr. Tanimoto in particular plays an important role in trying to help the victims of the bomb—most notably the Hiroshima Maidens, whose burns are so bad that they require plastic surgery. He becomes a minor celebrity in America and somewhat unsuccessfully tries to spread a message of peace in a time of nuclear escalation.

In the end, Hersey finds that the horrors of nuclear war are far from over—the citizens of Hiroshima still suffer from aftereffects, and nuclear escalation continues to threaten the entire world. Hersey also finds that these six people show, in the aftermath of the bomb and the war, remarkable feelings of good will, reconciliation, and pride.