The sudden, unexplained termination of a clandestine love affair during the London Blitz triggers a cascade of obsession and existential inquiry. Maurice Bendix, a novelist, finds his life consumed by the memory of his former lover, Sarah Miles, after she abruptly ends their relationship. Driven by a mixture of jealousy and lingering attachment, Bendix employs a private investigator to monitor Sarah, hoping to uncover the reason for her departure. The narrative unfolds through a non-linear, first-person perspective, alternating between Bendix's cynical observations and entries from Sarah's private journals. This structure forces the reader to navigate the tension between Bendix's subjective, often bitter interpretation of events and the spiritual complexity of Sarah's internal life.

Discussion often centers on the stark contrast between Bendix’s rationalist bitterness and the profound, transformative spiritual crisis experienced by Sarah. Readers frequently highlight the precision of the prose, noting how the author captures the claustrophobia of obsession within the backdrop of a decaying, post-war city. Critics often point to the book as a significant examination of the intersection between human desire and theological doubt. The pacing is deliberate, favoring internal character development over external action to emphasize the psychological weight of the protagonists' choices. Many readers find the shift in perspective between the two main characters to be the most effective mechanism for revealing the complexities of their shared history.