A mysterious cataclysm has depopulated London and returned the English countryside to a primitive, overgrown state. Following the collapse of civilization, the protagonist Felix Aquila navigates a landscape where nature has reclaimed the ruins of human industry. He seeks to establish his own standing in a society that has reverted to feudal structures and tribal warfare. The narrative framework shifts between a detached, observational account of the transformed geography and a more focused exploration of Felix's personal development within this altered world.

Discussion often centers on the book's status as a foundational text in the post-apocalyptic genre. Readers frequently highlight the author's meticulous attention to botanical and geographical detail, which grounds the speculative premise in a tangible reality. Critics often note the stark contrast between the lyrical descriptions of the landscape and the harsh, often brutal nature of the human interactions depicted. The pacing is deliberate, favoring atmospheric world-building over rapid plot progression, which appeals to those interested in the intersection of nature and civilization. Many readers find the lack of a clear explanation for the catastrophe to be a deliberate choice that emphasizes the permanence of the environmental shift.