The United States continues to devolve into total lawlessness as it struggles to recover from a pandemic that left billions dead. Gangs of convicts sweep through towns, raping and murdering with impunity. Opportunistic warlords build private armies with the hopes of expanding their influence. And infected survivors continue to mutate, growing stronger and more psychotic with each passing day. Deputy Marshal Mason Raines tracks a band of mercenaries responsible for poisoning hundreds of his fellow lawmen. Terribly outnumbered, he must resort to drawing the attention of an adversary even more dangerous than the soldiers of fortune. As the nation's last living marshal, Mason must once again remind his enemy that no one is above the law.

After the worst pandemic in mankind's history, anarchy threatens to break apart the United States. The government is years away from providing even the most basic necessities. Militias, gangs of convicts, and rogue soldiers face off in a violent free-for-all as they vie for power. Few safe havens remain. Big cities have been overrun with deformed survivors of the Superpox-99 pandemic. Smaller towns are being overtaken by authoritarians and lawless thugs. And congested interstates have become thoroughfares for desperate travelers and bandits seeking to capture women and supplies.

The Superpox-99 virus has wiped out nearly the entire human race. Governments have collapsed. Cities have become graveyards filled with unspeakable horror. People have resorted to scavenging from the dead, or taking from the living. The entire industrialized world has become a wasteland of abandoned cars, decaying bodies, and feral animals. To stay alive, U.S. Deputy Marshal Mason Raines must forage for food, water, and gasoline while outgunning those who seek to take advantage of the apocalyptic anarchy. Together with his giant Irish wolfhound, Bowie, he aligns with survivors of the town of Boone in a life and death struggle against a gang of violent criminals. With each deadly encounter, Mason is force to accept his place as one of the nation's few remaining lawmen. In a world now populated by escaped convicts, paranoid mutants, and government hit squads, his only hope to save the townspeople is to enforce his own brand of frontier justice.

Convinced that a militia leader holds the key to finally exacting justice, Deputy Marshal Mason Raines enters the destroyed city of Lexington. Traveling with the unlikeliest of allies, he must confront mutated survivors of the Superpox-99 virus as well as an elite group of military assassins sent to clean up evidence of President Pike's crimes.

An elite group of military assassins are preparing for an assault on the Greenbrier bunker, their mission to remove all traces of President Glass and her supporters. It is up to Deputy Marshal Mason Raines, his giant Irish wolfhound, Bowie, and a beautiful Mossad agent to stop them. But as they race across the country, new dangers threaten to disrupt their plans, including ravagers that terrorize the roadways in armored cars.