The book is written as a series of letters from Frances "Fanny" Hill to an unknown woman, with Fanny justifying her life-choices to this individual. At the beginning of her tale, Fanny Hill is a young girl with a rudimentary education living in a small village near Liverpool. Shortly after she turns 15, both her parents die. Esther Davis, a girl from Fanny's village who has since moved to London, convinces Fanny to move to the city as well, but Esther abandons Fanny once they arrive. Fanny hopes to find work as a maid, and is hired by Mrs. Brown, a woman she believes to be a wealthy lady. Mrs. Brown is in fact a madam (pimp) and intends the innocent Fanny to work for her as a prostitute. Mrs. Brown's associate, Phoebe Ayers, shares a bed with Fanny and introduces her to sexual pleasure. Mrs. Brown plans to sell Fanny's virginity to an ugly old man, but Fanny is repulsed by the man and struggles with him. She is saved from rape by Mrs. Brown's maid. After this ordeal, Fanny falls into a fever for several days. Mrs. Brown, realizing that Fanny's virginity is still intact, decides to sell Fanny's sexual favors to the exceedingly rich Lord B., who is due to arrive in a few weeks.Fanny spies on Mrs. Brown having sex with a large, muscular man. She talks to Phoebe, who assures her that it is possible for a young girl to have sex with a well-endowed man. She takes Fanny to spy on another prostitute, Polly Phillips, having sex with a handsome and well-endowed young Genovese merchant. Afterward, Phoebe and Fanny engage in mutual masturbation and Fanny looks forward to her first time having sex with a man.Soon afterward, Fanny meets Charles, a 19-year-old wealthy nobleman, and they fall in lust instantly. Charles helps Fanny escape the brothel the next day, and takes her to his flat at St. James's, London, and introduces her to his landlady, Mrs. Jones. For many months, Charles visits Fanny almost daily to have sex. Fanny works hard to become more educated and urbane. After eight months, Fanny becomes pregnant. Three months later, Charles mysteriously disappears. Mrs. Jones learns that he has been kidnapped by his father and sent to the South Seas to win a fortune. Upset by the news that Charles will be gone for at least three years, Fanny miscarries and falls ill. She is nursed back to health by Mrs. Jones, but sinks into a deep depression.