Frank Gresham is the squire of Greshambury Manor in the fictional county of East Basetshire. His wife is the aristocratic Lady Arabella, daughter of Earl de Courcy. Because Lady Arabella's and her husband's tastes are more expensive than their means, Gresham goes heavily into debt and has to sell part of his property to the uncouth, but extremely wealthy, Sir Roger Scatcherd.

Thus, it is determined by Lady Arabella that their son, Frank Gresham Jr., must marry an heiress to restore the family fortunes. Doctor Thomas Thorne is the senior Gresham's close friend and advisor. Doctor Thorne is a bachelor who has raised his niece Mary as if she were his own daughter. In reality, she is the illegitimate daughter of Sir Roger's sister and the Doctor's brother. (Sir Roger had killed Henry Thorne in a fit of passion over his sister's shame; the Doctor sent Scatcherd's sister to America; and Scatcherd served time in prison before going from rags to riches in the railroad contracting business.)

The novel tells the story of the apparently hopeless romance between Mary Thorne and Frank Gresham; and Gresham's mother's attempts to have him marry into a wealthy family. Ultimately, both Sir Roger and his reprobate son, Sir Louis, die of complications of alcoholism. It then turns out that Mary Thorne is sole heir (as the "eldest child" of his sister) to Sir Roger's fabulous fortune. Eventually, Frank and Mary marry and establish their home at Boxall Hill, which is actually built on the land that Gresham had sold to Scatcherd.