When the novel begins, things seem all right for our characters. Mr. Bingley and Jane appear to be falling in love, with all going well (except for a few minor embarrassing blips whenever Mrs. Bennet shows up), and Elizabeth knows her own mind well enough to save herself from the horrible mistake of marrying Mr. Collins. She enjoys putting Mr. Darcy in his place when she has a chance, and, except for Jane's sake, she doesn't care that the Bingleys and Darcy see themselves as superior to her family.
The situation quickly goes sour for all involved. First, Mr. Wickham shows up and talks trash about Darcy. Elizabeth is only too ready to believe whatever Wickham says. Then when it seems like Bingley is ready to pop the question, he goes to London – and doesn't return. Things are looking bleak.
After Darcy declares his undying love for Elizabeth, she lets him have it and tells him exactly what she thinks of him. The next day, Darcy hands her a letter that answers the two accusations she flung at him the day before. In the first part of the letter, he explains that he really believed that Jane didn't care for Mr. Bingley, and he sought to save his friend from making a drastic mistake. In the second part of his letter, he makes it clear that Mr. Wickham is the bad guy. Elizabeth ponders the letter for a whole chapter, and realizes how blind she has been.
It seems like Mr. Darcy and Elizabeth may reconcile and unite after all when Elizabeth accompanies her aunt and uncle to the countryside near his estate. Just when all seems to be going well, however, Elizabeth receives word that her silly little sister Lydia has done something awful – she's run away with Wickham. Nobody's sure if they will actually marry. If they don't, it will spell social ruin for the entire family. Elizabeth confesses the problem to Mr. Darcy before she leaves to help her family rectify the situation, thinking that Mr. Darcy will never, ever want to be connected to her family after this. All is solved when Lydia and Wickham are married, through Mr. Darcy's heroic efforts.
Bingley and Jane are reunited, though Darcy and Elizabeth seem to be further and further apart. All is not lost, however, as Lady Catherine de Bourgh shows up to prevent Elizabeth from accepting a proposal from Darcy. After Darcy learns that Elizabeth refused to agree to Lady Catherine's demands, he concludes that there may be some hope. Finally, Elizabeth and Darcy get engaged, to the shock of, well, everybody.