Fanny receives a second letter from Mary Crawford. The letter is vague and mysterious, warning Fanny not to believe any stories that might reach her concerning Henry and Maria. Fanny is surprised by the letter; Mary would never have mentioned anything unless a major scandal were brewing. Fanny had been almost convinced that Henry really was sincere in his feelings for her. That afternoon, Fanny is sitting in the front room with her father, who is reading a newspaper. The newspaper contains mention of a scandal in the Rushworth household; it claims that "Mrs. R" has run off with a "Mr. C." Fanny is shocked; this is an even worse scenario than Mary's letter had suggested.
A letter soon arrives from Edmund. Fanny is wanted at Mansfield immediately. Edmund will be coming to fetch her, and she is invited to bring Susan with her. Edmund has one more piece of news: in the aftermath of the scandal, Julia has eloped with Yates. Despite Sir Thomas's best efforts, no one has been able to find Maria and Henry.
Edmund arrives the next day to pick up Fanny and her sister. He is clearly distraught, although he will not open up to Fanny in Susan's presence. Upon their arrival at Mansfield, Lady Bertram rushes to greet Fanny, warm in her greetings to her adopted daughter. Fanny is delighted to be back home, despite the unfortunate circumstances. She finds Mrs. Norris in quite a state; having arranged Maria's marriage and often bragged about her role in it, she feels foolish at its sudden collapse. Mrs. Norris blames the entire situation on Fanny's rejection of Henry. Lady Bertram gives Fanny a fuller account of the situation: Sir Thomas had been informed of Maria's flirtations by an old friend and had been about to go to London to intervene when Maria and Henry disappeared. Servants had been involved in the elopement and now are threatening to make events public. The shock of all of this has caused Tom Bertram to relapse into illness.
The possibility of a match between Edmund and Mary has now disappeared, to Sir Thomas's dismay. Fanny must wait a few days before she has a chance to talk to Edmund about Mary. When she does, she finds out that Edmund went to see Mary immediately after Maria and Henry's disappearance, under the pretense of saying goodbye. He was horrified when Mary justified the runaways' conduct and began making plans for their societal rehabilitation. Mary, like Mrs. Norris, blames Fanny for rejecting Henry and causing the situation. In the course of the conversation, Edmund at last revealed to Mary his feelings for her, then told her in no uncertain terms what he thought of her character. Fanny is relieved that Mary has lost her hold over Edmund, and she finally gives her own opinion of Mary. She also tells Edmund that Mary wished for his brother's death for her own benefit. Edmund declares that he will never love another woman, and he tells Fanny that her friendship is all he has left.
The book concludes quickly. Mansfield Park slowly returns to normal. Sir Thomas is hard on himself for having allowed Maria to marry Rushworth. Julia asks for forgiveness, and she and Yates, who have married, are accepted into the family and seem eager to reform. Tom recovers his health and, changed by his experience, becomes a quiet, dependable young man. Edmund slowly regains his spirits, thanks to Fanny's company. Sir Thomas thinks over his errors in raising his children. Maria and Henry continue to live together, she hoping that they will marry. Eventually, they begin to quarrel; they separate. Rushworth has already divorced her. Mrs. Norris advocates allowing Maria back at Mansfield; when this is denied, Mrs. Norris and Maria leave for continental Europe, where they set up a quarrelsome little household. Sir Thomas is glad to have Mrs. Norris gone. The Grants, ashamed by the behavior of Henry (who is Mrs. Grant's brother), also leave Mansfield, as Dr. Grant has just gotten a position at Westminster. Mary goes to live with them, and has a hard time getting over Edmund.
Finally, Edmund begins to realize that he is in love with Fanny, and the two marry. The narrator is vague as to how long after Maria's elopement this takes place; presumably the turnaround has been fairly quick. Sir Thomas, chastened by recent experiences, is delighted at the match. Susan takes Fanny's place at Lady Bertram's side. William, too, continues to do well, and Sir Thomas is pleased at how well his "investment" in his nieces and nephew has paid off. Edmund and Fanny move into the Mansfield Park parsonage after Dr. Grant's death (although he had gone to London, he had continued to hold the living), and they live happily ever after.