A man navigates the desolate streets of 1665 London as the bubonic plague ravages the city, forcing him to document the collapse of social order and the mounting death toll. The narrator, a saddler living in the city, attempts to reconcile his desire to flee with his compulsion to witness the unfolding catastrophe. He moves through a landscape defined by locked doors, red crosses painted on homes, and the constant presence of death. The narrative framework is presented as a personal journal, utilizing a pseudo-documentary style that prioritizes observation and statistical reporting over traditional character arcs.

Readers and critics frequently highlight the work's uncanny ability to mimic the tone of a factual report, often leading early readers to believe it was a genuine historical document. Discussion often centers on the tension between the narrator's clinical detachment and the visceral horror of the events he describes. The pacing is noted for its deliberate, methodical progression, which mirrors the slow, inexorable spread of the disease throughout the city. Many observers appreciate the text for its atmospheric density and its role as a foundational piece of realistic fiction. The book remains a subject of study for its innovative use of narrative voice to ground speculative history in tangible reality.