Seven years after a devastating war, America's cities are semi-ruins and the government is run by a military junta who hold on to their "emergency" powers through strict food-rationing, heavy censorship and by declaring dissidents "enemies of the state." Citizens are offered prize money for the dead body of an "enemy," or for leading the security police ("sepos") to those so designated. Because Memphis night watchman Tom Rankin does not kill such an outlaw (a teacher who has posted copies of the Bill of Rights), he himself becomes a fugitive. Rankin flees down the Mississippi, hoping to board a ship to Australia, on the way encountering various bloodthirsty or venal citizens who want the bounty prize. Only after meeting some Underground members, whom he initially rejects, does Rankin finally take his stand.