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. As the nation's last living marshal, Mason must once again remind his enemy that no one is above the law.