Dr. Nolan orders Esther to be moved to Belsize, a different hospital ward in which the patients have greater privileges and do not undergo shock treatments. Joan is in Belsize, where she has walk privileges, shopping privileges and town privileges. The women in Belsize are fashionably dressed and made-up, and Esther watches several of these women gossip. There is also a society woman named Mrs. Savage who worries that her daughters will not be debutantes because of her time in the asylum. After speaking to a nurse who tells her about the "boobies in the state place that worry [her] off her feet," Esther worries that she will be demoted back to Caplan, then Wymark and finally the state institution.
The nurses do not serve Esther breakfast one morning, for she will receive shock treatment. Esther feels incredibly betrayed, but for the shock treatment but for the "bare-faced treachery" of Dr. Nolan. Esther shouts at Dr. Nolan that she said she would tell her, but Dr. Nolan says she thought it would only keep Esther awake. Esther makes Dr. Nolan promise that she will be there. Dr. Nolan gives Esther over to Miss Huey, a very tall woman who prepares her for the treatment.
Sylvia Plath develops the parallels between the mental institution and Esther's normal society in this chapter, in which Esther's new hospital ward essentially replicates the social order of the outside world. Even in an asylum, Esther cannot escape this fashionable society in which catty gossip and trends reign; these women do not have any concrete concerns, but rather manifest greater interest in their image in society, as when Mrs. Savage panics over jeopardizing her daughters' debutante status.
Dr. Nolan finally betrays Esther in this chapter, but this betrayal is less momentous and malicious than Plath had constructed this inevitable breach of faith to be. Although Esther initially describes Dr. Nolan's decision to administer shock treatment as treacherous, she seems to accept Dr. Nolan's decision and rationale as long as Dr. Nolan proves her devotion and concern for her. This does not fully absolve Dr. Nolan of responsibility for lying to Esther; it is more important for Esther's relatively mature and measured reaction to the act. This is more definitive evidence that Esther's mental health is significantly improving.
Esther awakes out of a deep sleep and sees Dr. Nolan, who tries to reassure Esther that it wasn't like it was before. She tells Esther that she will receive shock treatments three times a week. Joan and Esther both receive letters from Buddy Willard, and Joan asks whether Esther will let Buddy visit her at the asylum. Joan suggests inviting Mrs. Willard, for she has always liked Buddy's family more than Buddy himself. Esther is somewhat shocked by Joan's suggestion. Esther does not particularly like Joan, but she fascinates Esther, who believes she may have just made up Joan. Joan tells Esther that she likes her better than Buddy, and she stretches out on Esther's bed. Esther reminisces about a scandal at her college involving two supposed lesbians. She tells Joan that she does not like her, and that she makes her puke. Dr. Nolan schedules an appointment for Esther to get birth control pills, which will give her "freedom from fear, freedom from marrying the wrong person, like Buddy Willard, just because of sex." Her next step is to find a proper man.
Sylvia Plath leaves ambiguous the effects of the shock treatment on Esther; although Dr. Nolan attempts to reassure Esther that it was not like it was before, Esther registers little reaction to the electroshock therapy. She only asks whether she will have the treatment again and how often this will occur. This indicates some acceptance of the treatment. Barring the near-impossible scenario that Esther actually enjoys the shock treatment and believes in its benefits, her most plausible reaction is stoic acceptance.
With the recurrence of Buddy Willard in the novel comes a resumed interest in the theme of female sexuality. The idea that Buddy Willard might visit the asylum prompts reactions from Esther and Joan, neither of whom relish the idea of dealing with Buddy. In this chapter, Buddy comes to symbolize dominant male sexuality and power, for Esther and Joan both react to Buddy through exploring unconventional sexual methods. Whether Joan is a lesbian who attempts to seduce Esther is quite debatable, yet through the juxtaposition of Buddy Willard's letter and Joan's seeming invitation to Esther seems to indicate that Plath is constructing lesbianism as a reaction to the male dominance that Buddy represents.
Esther's decision to get birth control pills represents a different reaction to the male sexuality that Buddy symbolizes. Esther secures birth control pills as a means for female empowerment. For her, the birth control pills symbolize freedom and power. In contrast to her previous attempt to use sexuality by allowing herself to be seduced by Constantin, Esther is now an active agent of change. She no longer will wait for a man such as Buddy Willard to seduce her, but has decided to make an active attempt to free herself from the mores of society and find a man herself.
Joan tells Esther that she had a long conversation with her psychiatrist, Dr. Quinn, and she will become a psychiatrist herself. Esther thinks it is unfair that Joan is leaving before she does, even though Esther is merely staying at the asylum until her winter term begins. Esther meets a man named Irwin on the steps of Widener library at Harvard. He is a professor of mathematics, and Esther decides to seduce him after seeing his study. Esther has sex with Irwin, and afterwards she begins to bleed heavily. She goes to stay with Joan, for she is now staying with a nurse in Cambridge, and Joan realizes that she is hemorrhaging. When Esther goes to the hospital, the doctor tells Esther that she is a one in a million case.
Esther returns to the asylum, and Joan moves back in there as well, but one night Dr. Quinn awakes Esther to ask where Joan might be. Esther does not know, but Dr. Quinn awakes her later that night to tell her that Joan has been found in the woods by the frozen ponds. Joan has hanged herself.
Despite Esther's independence and defiant decision to empower herself through her sexuality, Plath continues to relate sexuality to violence and pain through this chapter, in which Esther suffers severe hemorrhaging when she has sex with Irwin. Although Esther's independent sexuality is a definite sign of her improvement and freedom, it is not without consequences. In fact, Plath succumbs to a judgmental moral attitude similar to the one which she condemns; Esther suffers great pain for having a sexual encounter with a man she barely knows, as if her hemorrhaging were punishment for her promiscuity.
Nevertheless, this chapter indicates that Esther has made a significant recovery through contrasting Esther's concrete independent attitude with the false confidence that Joan displays before her suicide. Plath contrasts Esther's resolve, even when making poor decision such as sleeping with Irwin, to the random behavior displayed by Joan Giling. Joan shifts from location to location, unsure of what she will be; this parallels the behavior demonstrated by Esther during the early chapter of the novel, and thus indicates how far Esther has progressed.
Esther prepares to leave the asylum that January, if she passes her interview with the board of directors. She realizes that people will treat her differently, either avoiding her or treating her gingerly. Her mother tells Esther that they will take up where they left out and "act as if this were a bad dream," but to a person like Esther in the bell jar, the world itself is a bad dream. Buddy Willard visits Esther, who feels that she has to reassure Buddy that she is all right. Buddy awkwardly asks whether she thinks that there's something in him that drives women crazy, and Esther bursts out laughing. He wonders because he dated Joan and then Esther.
Esther wonders whether someday the bell jar might descend again, and whom she will marry now that she has been in an asylum. Esther calls Irwin to confront him about the hospital bill from their encounter together. He agrees to pay, but when he asks when he will see Esther again, she responds "never." Esther feels that she is perfectly free. Esther attends Joan's funeral, despite Dr. Nolan's reassurance that she does not have to go.
Esther prepares to have her exit interview from the institution, and dresses herself for the occasion in "something old, something new" as if she were getting married. She compares this to a ritual for being born twice, "patched, retreaded and approved for the road."
Joan's suicide is the dramatic climax of the novel, effectively demonstrating through the contrast between the two characters that Esther is moving toward a complete recovery. Plath approaches the suicide almost entirely as an engine for the plot and not for its effect on Esther, whose minimal reaction to Esther's suicide emphasizes how little Esther cared for Joan. The only significant act related to Joan's suicide is Esther's decision to attend the funeral, and that serves primarily to demonstrate to Dr. Nolan that Esther is capable of making independent decisions.
Plath uses the final chapter to provide final comment on several of the plotlines throughout the novel. The comments by Buddy Willard about how he may have caused Joan's and Esther's insanity absurdly demonstrate his arrogance and self-importance. However, at this point Esther can dismiss Buddy as foolish where previously he would severely frustrate her.
Esther adopts a new tone in this chapter, specifically stating that she feels free and rejuvenated. While previous chapters have demonstrated this through Esther's actions and attitude, Plath makes this explicit through Esther's self-confident narration in which she states outright that she is "patched, retreaded and approved for the road." Plath still concedes that Esther may never fully be cured, as when Esther wonders whether she may be trapped again by the bell jar, but includes this only as a vague conjecture.
Still, Plath leaves Esther rejuvenated at the end of the novel but with her major problems unresolved. The negative comments by Esther's mother show that she is still a problem for Esther, while Dr. Nolan makes clear to Esther that she will face some scorn and delicate treatment upon leaving the hospital. In essence, very little has changed for Esther with regard to her relationships with family and friends. What has changed, however, is Esther's ability to cope and face the challenges that these may provide her.