The first letter begins with a short account of Fanny's impoverished childhood in a Lancashire village. At age 14, she loses her parents to smallpox, arrives in London to look for domestic work, and gets lured into a brothel. She sees a sexual encounter between an ugly older couple and another between a young attractive couple, and participates in a lesbian encounter with Phoebe, a bisexual prostitute. A customer, Charles, induces Fanny to escape. She loses her virginity to Charles and becomes his lover. Charles is sent away by deception to the South Seas, and Fanny is driven by desperation and poverty to become the kept woman of a rich merchant named Mr H—. After enjoying a brief period of stability, she sees Mr H— have a sexual encounter with her own maid, and goes on to seduce Will (the young footman of Mr H—) as an act of revenge. She is discovered by Mr H— as she is having a sexual encounter with Will. After being abandoned by Mr H—, Fanny becomes a prostitute for wealthy clients in a pleasure-house run by Mrs Cole. This marks the end of the first letter.