When the wealthy and eligible Earl of Rule, 35 years old, proposes marriage to Elizabeth Winwood, she resigns herself to marrying against her will to rescue the fortunes of her impoverished family. Her youngest sister Horatia, a 17-year-old young woman with a stammer, decides to take matters into her own hands, meeting with the Earl and persuading him to marry her instead of Elizabeth, thus leaving Elizabeth free to marry her true (but far less eligible) love. Part of the deal she proposes to Rule is that she will not interfere with his activities after their marriage. The wedding takes place and, as tacitly agreed upon, the Earl continues his association with his mistress, Lady Caroline Massey.