Plague Journal is Michael O'Brien's third novel in the Children of the Last Days series. The central character is Nathaniel Delaney, the editor of a small-town newspaper, who is about to face the greatest crisis of his life. As the novel begins, ominous events are taking place throughout North America, but little of it surfaces before the public eye. Set in the not-too-distant future, the story describes a nation that is quietly shifting from a democratic form of government to a form of totalitarianism. Delaney is one of the few voices left in the media who is willing to speak the whole truth about what is happening, and as a result the full force of the government is brought against him.

Thus, seeking to protect his children and to salvage what remains of his life, he makes a choice that will alter the future of each member of his family and many other people. As the story progresses he keeps a journal of observations, recording the day-by-day escalation of events, and analyzing the motives of his political opponents with sometimes scathing frankness. More importantly, he begins to keep a "mental record" that develops into a painful process of self-examination. As his world falls apart, he is compelled to see in greater depth the significance of his own assumptions and compromises, his successes and failures. Plague Journal chronicles the struggle of a thoroughly modern man put to the ultimate spiritual and psychological test, a man who in losing himself finds himself.