The narrative begins with an anonymous narrator visiting distant relatives at a country estate, where he discovers that his older cousin Laura, once haughty and distant, is secretly indulging in solitary erotic pursuits. Driven by a desire for discovery, the narrator initiates a physical affair with the estate's housemaid, Betsy, who acts as a key informant regarding Laura's habits and provides access to her secrets. Through a series of carefully planned stratagems and hidden observations, the narrator eventually confronts Laura and breaks through her defenses, introducing her to direct physical intimacy.
As the plot develops, Laura's younger brother Frank returns home from school, quickly becoming integrated into their illicit world through a series of mutually explored encounters involving both the narrator and Laura. The interactions expand in complexity, featuring intricate multi-party dynamics and detailed anatomical explorations that test boundaries and forge intense physical bonds among the trio. These secret rendezvous continue unabated, pushing the characters deeper into a shared culture of unbridled indulgence.
Complications arise when Laura fears she might be pregnant, threatening to expose their clandestine lifestyle. To solve this dilemma, the narrator devises a plan for Laura to marry Sir Charles Tracy, a wealthy and good-natured suitor who is himself drawn into their circle through a series of calculated seductions. The narrator engineers a situation where Sir Charles's massive proportions and subsequent initiation into the group provide Laura with both a legitimate husband and a failsafe against future suspicion.
The domestic arrangements shift as Sir Charles and Laura's impending marriage approaches, leading to a final series of elaborate farewell encounters that include Frank and Betsy. The narrative concludes with the successful marriage taking place without a hitch, concealing their unconventional history under the guise of respectability. While the characters eventually disperse into different lives—with Frank joining the army and Betsy emigrating to Australia—the legacy of their intense mutual awakenings leaves a permanent mark on all involved.
