The central conflict ignites when the beautiful and calculating Lizzie Eustace insists on keeping a valuable diamond necklace that her late husband’s family claims is an heirloom. Lizzie Eustace navigates the rigid social hierarchies of mid-Victorian England, employing her wit and charm to secure her financial future against the demands of her husband's aristocratic relatives. The narrative follows her attempts to maintain possession of the disputed jewels while managing the scrutiny of high society and the legal machinations of those seeking to reclaim the property. Trollope utilizes a third-person omniscient perspective to dissect the motivations of his characters, exposing the intersection of greed, reputation, and social standing. The world is defined by the strict moral and legal codes of the 19th-century British upper class, where the possession of wealth serves as the primary currency of power.

Readers and critics frequently highlight the novel's sharp wit and Trollope's ability to create a protagonist who is simultaneously frustrating and compelling. Discussion often centers on the ambiguity of Lizzie Eustace’s character, as she challenges the traditional expectations placed upon women of her era. The pacing is noted for its deliberate, expansive style, which allows for a thorough examination of the social pressures facing the characters. Many observers appreciate the balance between the central mystery of the diamonds and the broader commentary on the political and social structures of the time. The work is widely regarded as a significant example of Victorian realism that avoids simple moralizing in favor of a nuanced portrayal of human behavior.