The theft of a sacred Indian diamond from a young woman's bedroom during her birthday party sets off a complex investigation involving multiple narrators and shifting perspectives. The protagonist, Franklin Blake, attempts to recover the missing Moonstone while navigating the social constraints of Victorian England and the suspicions cast upon the household staff and guests. The narrative framework utilizes an epistolary style, where various characters contribute their own accounts of the events, creating a layered and often contradictory record of the crime. The investigation is hindered by the logical constraints of the era's social hierarchy and the physical limitations of the isolated country estate.

Discussion often centers on the innovative structure of the novel, which is frequently cited as one of the earliest examples of the detective genre. Readers highlight the effectiveness of the multiple-narrator approach in building suspense and providing diverse viewpoints on the central mystery. Critics often examine the thematic threads concerning British imperialism and the cultural significance of the stolen artifact. The pacing is noted for its deliberate, methodical progression, which allows for deep character development alongside the unfolding investigation. Many readers appreciate the balance between the atmospheric setting and the logical puzzle presented by the theft.