The sudden, unexplained termination of a clandestine wartime affair forces a novelist to confront the limits of his own obsession and the hidden motivations of his former lover. Maurice Bendrix, a writer struggling with the aftermath of his intense relationship with Sarah Miles, employs a private investigator to uncover why she abandoned him during the London Blitz. The narrative unfolds through Bendrix's first-person perspective, shifting between his present-day bitterness and his recollections of the past. As he tracks Sarah's movements, he encounters logical contradictions that challenge his cynical worldview and force him to re-examine the nature of faith and human connection.

Discussion often centers on the intricate psychological portrait of Maurice Bendrix and his transformation from a man of logic to one haunted by the inexplicable. Readers frequently highlight the stark contrast between the gritty, war-torn setting and the internal, spiritual conflict that defines the latter half of the narrative. Critics often note the precision of Greene's prose, which maintains a clinical detachment even while exploring themes of intense passion and spiritual crisis. The book is widely regarded for its ability to balance a conventional mystery plot with profound existential questions about the nature of love and belief. Many readers find the shift in perspective toward the end of the novel to be a significant turning point that recontextualizes the entire story.