When the German occupation of Paris shatters the comfortable existence of film producer Jean Casson, he is forced into a precarious double life as a reluctant operative for the French resistance. Casson, a man accustomed to the superficiality of the film industry, finds himself navigating a treacherous landscape where every social interaction carries the risk of betrayal. He must balance his survival instincts against the demands of intelligence agencies, all while attempting to maintain his personal integrity in a city under siege. The narrative follows his transformation from a detached observer of high society to a participant in the clandestine struggle against the occupying forces.

This work is widely regarded for its evocative atmosphere and its ability to capture the claustrophobic tension of occupied France. Critics often highlight the author's skill in grounding high-stakes espionage within the mundane realities of daily life. The protagonist's evolution from a self-interested civilian to a compromised agent provides a compelling study of character under extreme pressure. Readers frequently note the stylistic precision that mirrors the noir sensibilities of the era, creating a sense of constant, underlying danger. The narrative succeeds in presenting a nuanced view of the moral compromises required during wartime.