Isabel visits Pansy at the convent shortly before leaving for England. Here, she is surprised to encounter Madame Merle. Merle seems uncharacteristically awkward around her, even fumbling over her words, and Isabel realizes that Merle has guessed that she knows Pansy is Merle's daughter. Pansy seems slightly dejected, as though she has been confined in a prison; she says that she is now willing to do whatever her father asks of her but that she hopes Isabel will be with her to make things seem easier. Isabel promises to return from England to be with Pansy.
After she says good-bye to Pansy, Isabel is confronted by Merle, who announces that she has just realized something about Isabel's fortune: she says that it must have been Ralph who convinced Mr. Touchett to leave it to her. Isabel icily replies that she thought it was Merle's doing. Merle whimpers that she is miserably unhappy and reveals that she plans to travel to America, perhaps permanently, very soon.
Isabel makes the long journey to England. When she arrives, Henrietta and Mr. Bantling meet her at the station near Gardencourt. Mr. Bantling tells her that he has received a telegraph from the Touchetts, saying that Ralph's health is holding steady. Henrietta tells Isabel that she and Mr. Bantling are going to be married. Isabel feels somewhat let down by this news; it seems a very conventional thing for Henrietta to do, and Isabel had thought that Henrietta valued her liberty. But Mr. Bantling is a comforting presence, and Isabel congratulates him sincerely.
Isabel wanders through the portrait gallery at Gardencourt, which she has not seen for many years. She thinks about her past and wonders what would have happened if Mrs. Touchett had not brought her to Europe: she might have married Caspar Goodwood; she would never have known Gilbert Osmond; everything would have been different. Mrs. Touchett comes downstairs, and Isabel talks to her about their family and the neighbors at Gardencourt. Lord Warburton is planning to marry an English lady. Mrs. Touchett wonders whether Isabel regrets not marrying Warburton when she had the chance. Isabel replies that she does not, but Mrs. Touchett says that she will be hard to get along with if she is dishonest. Isabel opens up and admits that she is very unhappy with Osmond. She also admits to Mrs. Touchett that she dislikes Madame Merle; when she tells Mrs. Touchett that Merle is leaving for America, Mrs. Touchett is surprised and thinks that she must have done something very unpleasant to feel that she had to leave Europe. Isabel says that Merle treated her as a mere convenience; Mrs. Touchett replies that that is how Merle treats everyone.
Isabel sits at Ralph's bedside; he is too weak to talk. On the third night, he manages to speak to her and tells her that she is his angel. Isabel weeps, and Ralph tells her that he feels responsible for her problems: the money he secured for her is what drew Osmond to her in the first place and helped to punish her for her desire to see the world. Isabel says that she has been punished, but she does not think Ralph is to blame. Ralph asks if she will return to Rome, and she says that she does not know. Ralph urges her to remember that there has been love in her life and that she is still loved; no matter how bad things are for her, she is still loved.
That night, Isabel lies in bed, fully clothed in case Ralph should die. She remembers Ralph telling her about the ghost of the manor, which one cannot see unless one has suffered. Isabel suddenly sees Ralph standing next to her bed. She hurries to his room and finds Mrs. Touchett kneeling over him. He is dead. Mrs. Touchett tells Isabel to leave her and to be grateful that she has no children of her own.
Caspar Goodwood arrives in order to attend Ralph's funeral. Miserably, Isabel wonders whether she can bring herself to go back to Rome. She tries not to think about the problem. Mrs. Touchett tells her about Ralph's will: he has left his house to his mother and his library to Henrietta but nothing to Isabel. Isabel has an awkward meeting with Lord Warburton; she congratulates him on his marriage, and he invites her to call on the Misses Molyneux. She finds him strangely lifeless. When everyone is gone, Isabel sits on the garden bench—the same bench where Warburton proposed to her six years ago. Suddenly, Caspar Goodwood approaches her. He says that Ralph has asked him to help her, and he urges her not to return to Rome, but instead to leave with him. He kisses her deeply; Isabel feels as though she is drowning in the intensity of her emotion. She pulls herself away and runs into the house.
The next day, Goodwood finds Henrietta and asks her where Isabel has gone. Henrietta says that Isabel has returned to her husband in Rome. Goodwood is stunned; Henrietta takes him by the arm and leads him away.
And so, in the end, social convention seems to win out over American individualism and independence: Isabel returns to her agonizing marriage with Osmond, and even Henrietta decides to marry Mr. Bantling. Isabel's decision to return to Rome and to her husband is based on a variety of factors, each of which has been set up by the preceding chapters: her devotion to Pansy, her pride, her moral commitment to doing her duty even in times of suffering, her fear of the emotionally overwhleming Caspar Goodwood. Apart from Goodwood's obvious opposition, the principal resistance to Isabel's return to Rome seems to dissipate in this section. Ralph and Henrietta have been the staunchest champions of her independence and her freedom, and they each lose their voices—Ralph because he dies and Henrietta because she decides to give up her own independence in order to marry Bantling.
But just as James chose not to show us Isabel's engagement to Osmond or their wedding, he skips over her decision to return to Rome as well. We learn of it after the fact, and only second-hand, when Henrietta explains to Goodwood in Chapter 55 where Isabel has gone. James tends to use the elliptical technique whenever Isabel makes a decision that favors social custom over her independence, as though these moments are either intensely private or impossible to explain. In any case, the effect at the end of the novel is that Isabel simply dissipates, vanishing into the memory of her marriage; we are given no explanation of her thought process, and, for the first time, no hint as to what will become of her.
The novel solves its driving mysteries, then definitively answers its main conflict—social convention defeats individual freedom in a way that is not quite tragic and not quite morally inspiring—and then puts its story to rest. James's remarkable portrait of Isabel Archer has shown her development from an innocent, independent, optimistic young girl to a mature woman who has suffered and learned to commit herself to social propriety. After that lesson—which is not characterized by the novel as either right or wrong, and which is hard for the reader to accept as it is hard for Isabel herself—James seems to imply that there is nothing more to say.