A global pandemic systematically eradicates the human population, leaving Lionel Verney as the sole survivor in a desolate world. Verney, the protagonist, navigates the collapse of civilization as society crumbles under the weight of an unstoppable plague. He faces the logical constraints of a world where infrastructure, social order, and hope vanish, leaving him to confront the silence of a vacant planet. The narrative framework utilizes a retrospective, first-person perspective that emphasizes the isolation and psychological toll of being the final witness to humanity's extinction. Verney must contend with the physical decay of his surroundings and the internal struggle to maintain his sanity amidst total solitude.

Readers frequently highlight the stark contrast between the novel's intimate character studies and its grand, apocalyptic scale. Discussion often centers on the author's ability to project 19th-century anxieties onto a futuristic landscape, creating a sense of dread that remains relevant to modern audiences. Critics often note the pacing is deliberate, favoring philosophical reflection over rapid-fire action sequences. Many readers appreciate the bleak, atmospheric world-building that defines the protagonist's final years. The work is often compared to the author's other major contributions, with many arguing that its thematic depth regarding human extinction is particularly profound.