The protagonist, David MacKinnon, is a romantic idealist on trial for assault. Since the federal government fears he will repeat his action, he is given a choice: either allow trained psychologists to fix him, or be sent to an area known as Coventry. MacKinnon chooses to emigrate to escape what he sees as the boredom of a too-civilized society. He is sent to the rugged outland beyond the Barrier that separates Coventry from the rest of the world, where people who refuse to abide by social norms are exiled, rather than submit to radical psychotherapy. MacKinnon discovers that the peaceful anarchy he envisioned is in reality a bleak dystopia split into three separate "countries:"
New America, a corrupt democracy with a dysfunctional judicial system, that lies closest to Coventry's entry point and is the most populous of the three nations;
the Free State, ironically named — an absolute dictatorship ruled by the "Liberator" with an even harsher penal system, a nation frequently at war with New America though not at the time of the story; and
The Angels, remnants of the theocracy from "If This Goes On—", in the hills north of New America, living under a new "Prophet Incarnate" — it is implied they are the least populous of the three.
He is jailed on arrival in New America, losing everything he had brought through the Barrier with him. Befriended by a man David knows only as "Fader" Magee, he breaks out of jail. He learns that New America and the Free State are combining forces to attack the outside civilization. He and Fader break out of Coventry separately to warn the country from which he had emigrated of the imminent attack. Back in the world he had left, MacKinnon learns that Fader is actually an agent of the United States Army; and that by risking his life to warn the rest of the country, he has redeemed himself and no longer needs therapy.