Randy is a thirty-two-year-old former political candidate who takes intermittent work as an attorney. He lives a somewhat aimless bachelor lifestyle on his family's land in Fort Repose, maintaining a relaxed approach to life. When his brother sends a coded warning about an imminent nuclear attack, Randy abruptly shifts gears, utilizing his local connections and military reserve background to prepare his household for survival.

Mark is an officer in the United States Air Force stationed in Omaha, possessing high-level access to military intelligence. Dedicated and pragmatic, he foresees an imminent nuclear attack and prioritizes his family's safety by sending them to Florida. He chooses to remain at his post in the underground military bunker, fulfilling his duty to his country.

Helen is Mark Bragg's devoted wife and a fiercely protective mother. She is highly capable and quickly adapts to the crisis to manage Randy's household during the disaster. Accustomed to the structure of military life, she applies practical domestic skills to keep her family fed and organized while processing the trauma of their sudden displacement.

Dan is the dedicated town doctor in Fort Repose and Randy's closest confidant. Initially somewhat bitter from a difficult divorce and disillusioned with humanity, he finds renewed purpose as the community's primary healer during the crisis. He braves dangerous conditions to treat the sick and injured, serving as an essential pillar of the town's survival.

Elizabeth, commonly called Lib, is Randy's spirited and supportive girlfriend. She holds a degree in psychology and frequently applies her understanding of human behavior to the people around her. When disaster strikes, she refuses to give in to pessimism, offering Randy practical advice and steady emotional grounding.

Florence is a forty-seven-year-old manager at the local Western Union. She is a slightly judgmental neighbor who initially disapproves of Randy's lifestyle, viewing him as a shiftless womanizer. However, she possesses a strong sense of professional duty, staying at her post to manage communications as the crisis unfolds.

Alice is the astute local librarian in Fort Repose. She quickly recognizes the gravity of the military movements Florence mentions to her. When the disaster isolates the town, she finds renewed purpose in keeping the library open, providing essential information and distraction to a community cut off from modern media.

Ben is Mark and Helen's adolescent son. Because he grew up entirely during the Cold War, he approaches nuclear threats with stoic practicality rather than panic. He immediately steps up to help defend the household, taking his responsibilities to protect the family's resources seriously.

Peyton is Mark and Helen's young daughter. Like her brother, she accepts the reality of the war with surprising calm. She is highly observant and resilient, though she becomes frustrated by being restricted to indoor chores during the crisis, harboring a strong desire to prove her usefulness to the household's survival efforts.

Malachai is a hardworking and dependable neighbor of Randy. He relies on his family's artesian well and extensive practical skills to help sustain the local households when modern infrastructure fails. He is courageous and volunteers for dangerous tasks to keep the community safe.

Two-Tone is Malachai's brother and Missouri's husband. He possesses less drive than his brother and avoids hard labor when possible, but he holds valuable knowledge regarding agriculture and distillation that proves surprisingly useful to the community's survival.

Missouri is a hardworking maid who cleans for both Randy and the McGovern family before the disaster. She provides sensible, grounded observations about the families she works for and cares deeply for her own family's well-being.

The patriarch of the Henry family and a local preacher. He is an expert fisherman and a respected figure in the community whose fiery sermons warning of "Alas, Babylon" inadvertently mirror the military code Randy receives regarding the nuclear attacks.

Elizabeth's father, who initially refuses to believe an attack is imminent because he assumes his connections in the Pentagon would have informed him. He is forced to adapt his worldview drastically when disaster strikes, eventually utilizing his mechanical skills to contribute to the Bragg household's survival.

Elizabeth's mother, who suffers from severe diabetes and relies on a steady supply of insulin to survive. She represents the intense vulnerability of individuals dependent on modern medicine and refrigeration in a sudden infrastructure collapse.

The proud, stubborn president of the Fort Repose bank. He heavily ties his personal worth and identity to the town's financial structure and his status within it. He holds a long-standing grudge against the Bragg family due to an old slight from Randy's father.

Randy's ex-girlfriend and Pete's sister. She lives in Pistolville and is described as a fiercely independent woman. Her habit of hoarding valuable items represents a different, more materialistic approach to the crisis compared to the practical survival skills of the Bragg household.

A local politician who defeated Randy in a race for state representative by campaigning against racial integration. He is known for his greed, shady dealings, and willingness to exploit chaotic situations to amass personal wealth, notably collecting large amounts of contaminated jewelry.

A retired Navy officer who lives near the Henrys. His hobby of operating a short-wave radio provides the isolated community with crucial military updates and external news regarding the state of the war and the rest of the world.

A pilot and friend of the Bragg brothers. He serves as a critical link to the military operations outside of Fort Repose, providing necessary updates regarding the broader scope of the national emergency.

Rita's brother and the manager of the local supermarket in Fort Repose. He attempts to manage the chaotic rush for supplies as the crisis begins, dealing with the sudden scarcity of common goods.

Missouri and Two-Tone's son. He quickly adapts to the new reality of the town, taking on serious responsibilities like guarding the local livestock alongside his peers to ensure the community's survival.