Clarissa Harlowe, the tragic heroine of Clarissa, is a beautiful and virtuous young lady whose family has become wealthy only recently and now desires to become part of the aristocracy. Their original plan was to concentrate the wealth and lands of the Harlowes into the possession of Clarissa's brother James Harlowe, whose wealth and political power will lead to his being granted a title. Clarissa's grandfather leaves her a substantial piece of property upon his death, and a new route to the nobility opens through Clarissa marrying Robert Lovelace, heir to an earldom. James's response is to provoke a duel with Lovelace, who is seen thereafter as the family's enemy. James also proposes that Clarissa marry Roger Solmes, who is willing to trade properties with James to concentrate James's holdings and speed his becoming Lord Harlowe. The family agrees and attempts to force Clarissa to marry Solmes, whom she finds physically disgusting as well as boorish.
Desperate to remain free, she begins a correspondence with Lovelace. When her family's campaign to force her marriage reaches its height, Lovelace tricks her into eloping with him. Joseph Leman, the Harlowes' servant, shouts and makes noise so it may seem like the family has awoken and discovered that Clarissa and Lovelace are about to run away. Frightened of the possible aftermath, Clarissa leaves with Lovelace but becomes his prisoner for many months. She is kept at many lodgings and even a brothel, where the women are disguised as high-class ladies by Lovelace himself. She refuses to marry him on many occasions, longing to live by herself in peace. She eventually runs away but Lovelace finds her and tricks her into returning to the brothel.