Set against the backdrop of a post-apocalyptic America, Alas, Babylon follows the unfolding events in Fort Repose, Florida, during the year after a devastating nuclear war. The narrative revolves around Randy Bragg, a thirty-two-year-old lawyer and ex-military officer, and his efforts to preserve a semblance of order and civilization amidst chaos. Together with his community, Randy navigates the challenges of a world stripped of its modern comforts and governed by new rules.

The Imminence of Disaster

The novel begins with Randy receiving a cryptic message from his brother Mark, an Air Force colonel involved in Strategic Air Command Intelligence. The message ends with "Alas, Babylon," a pre-arranged signal indicating impending catastrophe. Mark's conviction that a nuclear attack is imminent leads him to entrust Randy with the care of his wife, Helen, and their children, Ben Franklin and Peyton. His fears are swiftly realized the next morning when two nearby cities are obliterated by atomic bombs.

The Chaos Unleashed

Randy is jarred awake by the tremors and ominous orange glow of the explosions, and his niece Peyton suffers temporary blindness from witnessing the flash. As Fort Repose descends into turmoil, Randy witnesses firsthand the collapse of societal norms. The roads are clogged with refugees, escaped convicts roam free, and businesses come to a standstill. In this new and harsh reality, the notion of charity quickly fades as survival becomes paramount, with the absence of electricity, running water, and communication reducing many to squalid conditions.

Building a Community

Amidst the anarchy, Randy adopts a pragmatic approach, focused on maintaining a semblance of order. He disposes of contaminated bodies, including that of a local politician, to prevent further hazards. In a bid to forge a cooperative and resilient community, Randy gathers a group comprising Helen and her children, his fiancée Lib McGovern and her father, Dr. Dan Gunn, and other local residents, including a retired admiral and the Henry family. Together, they manage to stave off the descent into lawlessness that plagues others.

Confrontations and Leadership

As the self-appointed leader of Fort Repose, Randy takes decisive action against the "highwaymen" who threaten the community’s safety, effectively instituting martial law and restoring order. In the spirit of rebuilding, he establishes a legal framework for marriage, becoming its first beneficiary by marrying Lib McGovern. His leadership and the collective resolve of the group ensure their survival and solidarity in the face of adversity.

A New Beginning

A year after the catastrophic events, a helicopter lands, piloted by a friend of Mark, delivering news of a bittersweet victory for the United States. Although Mark is presumed dead, Fort Repose is confirmed to be free from radiation. Despite the chance to relocate, Randy and his community choose to remain in Fort Repose, ready to confront the challenges of the "thousand-year night" together. This choice underscores their commitment to their reborn society and their resolve to carve out a future from the ruins of their world.