Sarah meets her mother, Ada, for lunch. Ada, a suspicious and hard woman, quickly extracts the story of Sarah's romance with Billy. She then warns her daughter that every tenth condom has been pricked with a hole and goes on to assert that if Sarah has sex with her suitors, they will never marry her. Ada wishes her daughter worked in a place where she would have the opportunity to meet men, not at the munitions factory that is causing her skin to turn steadily more yellow. Ada's greatest ambition for Sarah is that she marry a man with a stable income; if the man dies after their marriage and she is left with an inheritance, all the better. In Ada's mind, men are predatory and women are dependent. Ada does not believe men and women can love one another; Sarah finds this approach to life very depressing. At the end of their meal, Ada warns Sarah that Billy is only interested in her for sex and advises her daughter to be cautious.
Sassoon meets with Graves and they discuss his imminent return to France. Their conversation is cold; it seems as though a distance has grown between them. Graves tells Sassoon that he worries about him because Sassoon does not think about the future anymore. The lieutenant, meanwhile, refers to the mounting death rates and tells Graves that if he had any real courage, he wouldn’t “acquiesce” the way he has (198). Offended, Grave invokes a gentlemanly code of honor where keeping one’s word reigns supreme, reminding Sassoon about the promises he made upon enlisting.
After their argument, Graves informs Sassoon that Peter, a boy Graves was very fond of, was arrested for soliciting outside the barracks and will be sent to Dr. Rivers for treatment. Graves goes on to say that since the incident, he has begun writing to a woman in order to focus his attention on more "normal" relationships. Graves insists he is not, nor has he ever been, a homosexual, “even in thought” (199). Sassoon is taken aback by this unwarranted admission.
Sarah goes to work at the munitions factory during the night-shift, chatting with her co-workers while they wait to enter. The women joke about all the homosexual men in the army in a somewhat vulgar manner. Looking around her, Sarah observes that these women do not look human: the factory has dyed their skin yellow and endowed each one with a crown of frizzy copper hair. She asks about the whereabouts of her friend Betty and learns that Betty attempted to give herself an abortion with a coat-hanger and accidentally punctured her bladder. Betty had to be taken to the emergency room, where a condescending doctor lectured her.
Dr. Rivers finishes his rounds that evening with Sassoon, who is anxious to hear if the War Office has agreed to send him back to France. After the psychologist explains that he has gotten no word, Sassoon mentions Graves’s story about Peter and subsequent rejection of his homosexuality. The lieutenant admits that he thought social attitudes towards homosexual men were improving. Dr. Rivers agrees but theorizes that during a war, men are encouraged to develop extremely close and brotherly relationships in combat; the intimacy of these relationships makes many men nervous. Therefore, exaggerated posturing against homosexuality is a way for soldiers to create a distinct separation between the bonds of war and romantic love between two men. The psychologist warns Sassoon that making his private life public could result in severe persecution. Sassoon replies that he does not want to repress his beliefs or desires. Harshly, Dr. Rivers compares him to Don Quixote and tells him to grow up.
Prior attends his board hearing. The internal tension between his ambition to prove himself on the battlefield and his desire to live nearly paralyzes Prior, and Dr. Rivers empathizes with him. Outside the hearing, Sassoon and several other soldiers wait for their own hearings, increasingly nervous as their appointments are further and further delayed. Angry that he is being made to wait after preparing himself to die for his country yet again, Sassoon leaves abruptly. When Dr. Rivers comes to find Sassoon to bring him into his hearing, he is long gone.
After learning that he will be excused from further service, Prior sobs because he wanted to return to the front. Dr. Rivers explains that it was not his mental condition but his asthma that rendered him unfit for battle. Prior is ashamed, claiming he’ll never know how he would have performed and fearing that his failure will haunt him. Dr. Rivers admits that if he were in Prior’s position he would feel similarly because they have both been socially conditioned to do so. The psychologist tries to convince his patient that everyone who survives a war experiences guilt, trying to help him see that his reaction is perfectly normal. Prior explains that his asthma always made him want to prove himself more, but his mother was always holding him back for his own safety. He remarks that Dr. Rivers reminds him of his mother. Billy says he will write to the psychologist and the two men say goodbye amicably.
Dr. Rivers eats dinner and ruminates over Sassoon’s disappearance. Nobody has seen the lieutenant since he skipped his board hearing and the psychologist worries that Sassoon might have gone to London to make another anti-war statement. Dr. Rivers speculates that with the mounting death tolls, the War Office will be particularly sensitive to criticism and would likely have Sassoon declared insane if he renews his protest. Meanwhile, another doctor at the table speaks insensitively about poor women and procreation.
Sassoon finally returns to Craiglockhart, acting like a school boy who has skipped class. Dr. Rivers demands an explanation for his behavior, but Sassoon cannot produce a satisfying one. He claims that he was upset for being made to wait and was late for an appointment to have tea with a friend. Eventually, Sassoon admits that he wanted to get a second opinion from another esteemed psychologist in London so that if the War Office attempted to have him declared insane, he would have the opinions of two renowned doctors to support his sanity. Despite this, Sassoon made no effort to get a second opinion after he walked out, he simply went to have tea with his friend. Sassoon speaks about the possibility of reviving his protest against the war, but he also says that he intends to return to France regardless. Dr. Rivers does not understand Sassoon's contradictory position but is grateful that the lieutenant is going to return to the front after all.
Prior sneaks into Sarah’s yard, waiting for a signal before climbing into her room through the window. He knows he should feel free after being released from duty, but he finds this freedom to be “hollow” (214). Trying to remain quiet so as not to alert the landlady and the other tenants, Billy and Sarah whisper nervously. The couple, shy and sweet, lay on the bed together for a moment, anticipating sleeping together. Sarah says she is happy that Billy will not be returning to war, triggering a brief flashback. Billy considers telling her about his war experiences because he wants Sarah to know him “deeply,” but ultimately decides that he needs her to remain ignorant so he can hide in her innocence (216). They joke for a few moments before Billy announces that he loves her; after some brief hesitation, Sarah says she loves him as well.
At the Conservative Club, Sassoon and Owen laugh over a book of awful poetry that was given to the lieutenant by the author. Sassoon makes a gift of the book to Owen, who remarks that whenever Sassoon does something intimate, he does it in a way that is “impossible to take seriously” (218). Owen admits that Craiglockhart will be very lonely without Sassoon and Dr. Rivers. He reflects that he, like Sassoon, will soon be forced to leave and give up his bed for a needier patient. Sassoon gives his friend a letter of introduction to Robert Ross, a key figure in the London literary scene, and leaves without officially saying goodbye. Owen tries not to think about all he has lost.
The beginning chapters of Part IV of Regeneration focus heavily on women’s issues during World War I. Sarah’s mother Ada espouses a profoundly cynical view of relations between men and women; she sees marriage as little more than a business transaction. This represents a more practical and traditional way of thinking that emphasized the economic benefits of marriage over the romantic ones. Sarah undercuts her mother's opinion by continuing to spend time with Billy and even admitting to loving him. The changes women are experiencing during the war is one of Regeneration’s recurring themes: the women in the novel have increased freedom, higher wages, and a wider choice of roles in society. This societal shift is reflected in the physical transformation of the female factory workers: their skin grows yellow and their hair turns frizzy and copper-colored. They are very literally changed in the wartime environment. Yet the new opportunities available to women come with severe costs, as well. Sarah’s friend Betty has unprotected sex and, lacking access to reliable medical care, attempts to perform an abortion herself. Then, while seeking care for her self-inflicted injuries, a male doctor rebukes Betty condescendingly. Betty's cautionary experience conforms to Ada’s concerns about Sarah’s carefree love life.
Just as Ada makes Sarah aware of the dangers of being unmarried and sexually active, Barker also reveals the consequences for homosexual behavior in England during this time. Graves pointedly tells Sassoon that one of their old friends has recently been arrested for soliciting gay sex and explains that the incident has spurred Graves to start a correspondence with a woman. Later, Dr. Rivers reinforces Graves’s concerns about being perceived as a homosexual, explaining that Sassoon could face persecution if his sexual orientation becomes public. The psychologist compares gay romantic feelings to the platonic intimacy between men in a combat situation. He insinuates that society reviles homosexuality in order to underline the distinction between romantic love between men and the brotherhood that emerges on the battlefield; Rivers's point serves to further emasculate men in combat. Contemporary opinion during this time condemned homosexual men as feminine and weak; accusations of homosexuality based on close relationships with fellow soldiers would have been terrifying for many men. In a similar vein, Prior reinforces Dr. Rivers's own emasculation yet again by telling the doctor that he reminds him of his mother.
Several men, most notably Sassoon and Prior, face the possibility of returning to war. Both characters experience contradictory reactions to the potential transition. Sassoon has publicly denounced the war as meaningless and cruel, yet agrees to return to battle so he can assuage his guilt for leaving his men behind. Prior wishes to return so that he can prove himself, yet he strongly fears the possibility of death. Both harbor shame for being safe at Craiglockhart: Sassoon feels that he has disappointed his fellow officers and soldiers, while Prior believes that his breakdown has shattered the image of him as a strong and competent man. Dr. Rivers confirms that feelings of shame or guilt are the burden of all those who survive a war. Through these specific examples, Barker illustrates that there is no simple reaction to something as complex as participating in combat.
Sassoon’s decision to return to France sparks conversations with Graves and Dr. Rivers about competing notions of responsibility. Graves believes that a man’s ultimate responsibility revolves around contracts and institutional loyalty; in Graves's mind, Sassoon has agreed to fight and must complete his obligations to the British military, regardless of his feelings. Sassoon, on the other hand, feels a responsibility to his fellow soldiers that are dying in vain, and, more broadly, a responsibility to uphold his own ideals. Sensing that the motivations behind the war are unjust, Sassoon feels an obligation to denounce it. Furthermore, he feels repulsed by the fact that he is expected to hide his sexuality. Dr. Rivers mocks Sassoon's quest to be true to himself by comparing him to Don Quixote, a famous literary character who embarked on fantastical and useless missions. The psychologist feels a sense of responsibility to the military but also to Sassoon; his advises the lieutenant to hide his homosexuality in an attempt to protect Sassoon from facing the dire consequences.
In an interview, Pat Barker once explained that the “major theme—of all [her] work—is recovery” (Nixon 3). This is reflected elegantly in the novel’s title: Regeneration. Part IV has many examples of how loving relationships can have a positive impact on a character’s recovery. Through his intimacy with Sarah, Billy is able to reconnect with the world. Sarah brightens his mood whenever he encounters her; eventually, he has the courage to admit that he loves her, thus making himself vulnerable. This is a major accomplishment for the previously detached and vicious patient. Similarly, Owen and Sassoon are able to build a supportive friendship that assists each man in his recovery. Under Sassoon’s mentorship, Owen blossoms as a poet, finally channeling and processing his memories of the war. With Owen’s companionship, Sassoon becomes less aloof, finding joy and human connection in helping the young poet. These relationships reinforce the novel’s major theme - the cycle of pain and destruction followed by regrowth and recovery.