The Wilks family is the target of one of the duke and the king's most conniving scams. The two cons learn from a local young man that Peter Wilks, a fairly wealthy local tanner, has just passed away. Peter Wilks' nieces—Mary Jane, Susan, and Joanna (who Huck refers to as "the hare-lip")—are about to inherit the family estate, since their mom and dad (who was Peter's brother) passed away the year before.
Peter had been hoping to see his other two brothers, William and Harvey, before he died, but they hadn't yet arrived from England. The duke and the king, being the con-men extraordinaires that they are, decide to pose as the two missing brothers in attempt to steal the family's riches.
Unfortunately for the cons, the Wilks ladies are very likeable, lovely young women, and Huck just can't stand by and let the duke and king take the girls' money. Huck grows especially fond of Mary Jane, the oldest of the group. She's "awful beautiful" (25.5), and "handsome" (25), and basically Huck has a giant crush on her. Her compassion for her family's slaves has a big impact on Huck's ethical questioning.
Aw, we even have kind of a crush on her ourselves.