Frédéric travels and lives several years idly, having affairs and not working. One day in March 1867, Madame Arnoux enters his study. She has been living in Brittany. They renew their declarations of love for each other and take a walk, reminiscing about their past. Back home, she takes off her hat, and Frédéric is shocked to see that her hair is white. He covers up his shock by flattering her. He thinks she has probably come here to give herself to him, and he is uninterested. They run out of things to say, and she leaves.
Frédéric and Deslauriers, reunited, discuss their lives and their friends. Madame Dambreuse has married an Englishman. Louise left Deslauriers for a singer. Martinon is a senator, Hussonnet has earned total control of the press and theatres, Cisy has eight children, and Pellerin has become a photographer. Neither friend knows what has happened to Senecal. Frédéric speculates that Madame Arnoux, recently widowed, is in Rome with her son. Deslauriers tells Frédéric he saw Rosanette recently in a shop, with an adopted child. She is now fat. He reveals in his description that he had briefly been her lover once Frédéric left her, and Frédéric pretends not to mind.
Deslauriers explains to Frédéric what “calf’s head” refers to: in England, some independents parodied a ceremony practiced by the Royalists by eating calves’ heads and drinking wine out of the skulls. In France, revolutionaries had started the same secret society.
The two friends reminisce about their past, particularly an incident when they were much younger and went to see a woman called La Turque, who ran a brothel. Deslauriers and Frédéric snuck over to the brothel, but Frédéric became immediately overwhelmed by the women, and the friends run away. They agree that this is their happiest memory.
Frédéric’s endless infatuation with Madame Arnoux leads to the definitive end of his relationships with Rosanette, Madame Dambreuse, and Louise. He leaves Rosanette to try to stop Madame Arnoux from leaving and accuses her of being behind the sale of the Arnouxes’ belongings, grandly cutting all ties to her by telling her he’s never loved anyone but Madame Arnoux. His wild claims prompt Rosanette to tell him to go to her—and this seems to be the command Frédéric has been waiting for. Unable to take definitive action on his own, Frédéric now has someone else telling him to do it; but it is too late, since Madame Arnoux is already gone. Frédéric, foolishly believing that Madame Dambreuse will never find out about his attempt to save Madame Arnoux, is blindsided by Madame Dambreuse’s cruelty in facilitating the sale of the Arnouxes’ belongings, and he leaves her too. Alone now, he makes a last-ditch effort to win Louise, but he is too late. His love for Madame Arnoux has finally cost him every other woman in his life.
Madame Arnoux’s final visit to Frédéric marks the end of their strange affair and reveals the limits of Frédéric’s feelings for her. Frédéric has always managed to rekindle his love for her whenever she crossed his path; when she visits him after several years of absence, he feels great delight and easily extols his happiness and love once more. However, her white hair kills any possibility of continued romantic feelings. Her drastically changed physical appearance is a revelation: although he loves Madame Arnoux, he loves the Madame Arnoux who existed many years ago. This aging, struggling, unhappy woman no longer interests him; in fact, he thinks that becoming her lover will be annoying. He continues declaring his love, but he is speaking to a memory, not the actual woman before him. All along, he has believed Madame Arnoux to be beyond human, almost a religious figure, and his easy dismissal of her demonstrates that he wants her on a pedestal, as a dream, not as a woman in all her flawed, real, aging, human glory.