In the waning years of World War I, decorated officer Siegfried Sassoon writes an anti-war declaration, causing his superiors to send him to Craiglockhart War Hospital in Scotland, where the psychiatrist Dr. Rivers will determine whether or not he suffers insanity or war neurosis. When Rivers and Sassoon first meet, they get along very well, each impressed by the other’s decency and intelligence, although Rivers makes it clear that it his duty to treat Sassoon over the next three months and convince him to return to combat. Sassoon reveals that he is a writer and in communication with several famous pacifists. Rivers also meets Robert Graves, Sassoon’s superior officer and close personal friend, who reveals that Sassoon suffered brief but significant hallucinations in the past, but overall is an exceptional commander and dearly loved by his troops.
Among his many patients—the worst afflicted of which is a young man named David Burns, who is so traumatized that he cannot eat without instantly vomiting—Rivers meets a particularly difficult officer named Prior who suffers from intermittent mutism, some memory loss, and night terrors, as well as bad asthma that somehow escaped the enlistment board’s notice. Prior tends to be combative towards Rivers and resists therapy, refusing to engage with his emotions or reflect on the traumatic events that landed him at Craiglockhart. Rivers is frustrated by this but also recognizes that addressing one’s emotions is a difficult thing for men to do, since they have been raised from childhood to believe that to be masculine is to be stoic and repress all feelings. For his patients to explore feelings of fear and tenderness requires that they reimagine what manhood truly looks like, though Rivers believes this emotional awareness will ultimately make them healthier soldiers and human beings. Rivers also dreams of experiments he used to do at Cambridge with a friend and fellow researcher named Head, where he purposefully inflicted pain on Head so they could measure the regeneration of a severed nerve in Head’s arm, a memory that Rivers notes reflects his own ethical dilemma of leading his patients through painful memories in order to restore their psychological functioning.
Rivers continues to meet with Prior, who is still hostile and resents the doctor-patient dynamic of therapy. Prior says that he wishes that Rivers would be a person rather than a “strip of empathic wallpaper,” and that Rivers needs to recognize that he, Rivers, practices his own forms of repression. Meanwhile, during their therapy sessions, Sassoon reveals that he is privately a homosexual. Rivers is very accepting of this, but recommends that Sassoon keep that part of his life as discreet as possible, since many people will want to use anything they can to discredit his protest, and Sassoon’s illegal sexual orientation would make a prime target for public slander. Soon, Sassoon’s anti-war declaration is published in the newspaper, drawing public attention to Craiglockhart.
Prior is confined to sick bay for some time due to a particularly bad asthma attack, but once he is released he begins to open up about some of his combat experiences and the absurdity of war, though he still cannot recall the main traumatic event. While eating alone in a café in Edinburgh, Prior meets a woman named Sarah who works in a munitions factory and they go on a date together. Meanwhile, Sassoon is befriended by a fellow patient at Craiglockhart named Owen, who is himself a poet and a great fan of Sassoon’s published work. Sassoon suggests that they should work on Owen’s poetry together.
Prior arrives in Rivers’s office late one night, notably less obstinate than usual and visibly depressed, finally admitting much about his nightmares that he’d formerly withheld. Rivers offers to hypnotize him to help him remember his main traumatic incident and Prior agrees. In a trance, Prior recalls cleaning a trench, shoveling the body parts of two of his men who had just been killed by an artillery strike into a bag, when he finds himself holding a single eyeball in his palm, which triggers his mind to break down and leaves him mute. When Prior awakes from the hypnosis memory, he is both horrified and angered that there was not more to it. However, he grabs Rivers by the arm and begins head-butting him in the chest, which is as close as he can get to asking Rivers for physical affection, since he is a man.
Rivers continues to meet with Sassoon and their friendship grows, though Sassoon chafes at the thought of his friends dying while he sits safely and comfortably in Craiglockhart. Sassoon’s will to protest seems to be weakening. Rivers, however, finds his own support of the war challenged more and more by Sassoon’s arguments and the trauma he sees the war inflict on his young patients. Sassoon and Owen’s relationship continues to grow as well, and Owen becomes visibly more confident and quite skilled as a poet.
Prior visits Sarah again, and they go on a date to the beach, where they sleep together in a thicket. Prior is internally conflicted, since he feels joy for the first time in years but also resists it, since she is a civilian who knows nothing of the horrors he’s seen. Rivers, meanwhile, shows symptoms of his own developing war neurosis from the stress of the hospital, so his commanding officer sends him on three weeks of leave. The night before he departs, Sassoon has another hallucination and desperately wants to meet with Rivers, but misses him, and realizes that the absence feels the same as when his father abandoned him as a child.
Rivers spends most of his leave near London, visiting his brother and Head, who offers Rivers a job as a psychologist for the Royal Flying Corp, which would allow him to be back in Cambridge and let them work together once again. Rivers considers it, but is unsure. For the last few days of his leave, Rivers visits his friend Burns, who’s been discharged on account of his mental condition, in a little seaside village. Burns seems to be recovering to some degree, but during a bad storm has such a terrible breakdown that Rivers thinks to himself that no war or sense of duty could possibly justify the pain that’s been inflicted on Burns. The day after, Burns speaks more openly about combat than he ever has, and River thinks that Burns may someday live a functional life, though he will never lead a normal one.
After Rivers returns to Craiglockhart, he meets with Sassoon, who tells him about the hallucinations and believes that they are a sign of his guilt at being safe while others fight, so he resolves to return to combat in spite of his protest. After Sassoon learns from Graves that a friend was recently arrested for his homosexuality, Sassoon and Rivers discuss the tragic irony and hypocrisy of society for demanding that men love each other as comrades but denies them loving each other any further than that. However, Rivers believes that this intolerance is all the more reason for Sassoon not to make more disturbance, because he does not want to see Sassoon targeted, besmirched, or arrested.
Sassoon and Prior are due for examination on the same day, but Sassoon skips his, infuriating Rivers. Prior is examined by the medical board and discharged from service due to his asthma. He is angry and bitter, but in some sense relieved he will not need to return to combat, and speaks fondly to Rivers in their last moments, promising to keep in touch. Rivers, for his part, feels fond of Prior as well, despite how frustrating Prior has sometimes been. After leaving Craiglockhart, Prior sneaks into Sarah’s room where they lie together and say that they love each other; Prior feels as if he’s found a “safe haven” in Sarah. Sassoon and Owen meet one last time, since Owen is also about to leave, though Sassoon has to stay another month since he missed his examination. Owen feels deeply for Sassoon, though is afraid to show it, and at their parting all the affection the two can muster is a mere pat on the shoulder.
Rivers decides to take the job that Head offered to him and moves to London, though he will have to return to Craiglockhart in a few weeks for Sassoon’s second examination. The last time he sees Sassoon before going to London, Sassoon is visibly withdrawn and dejected because Rivers is leaving, and the pacifists are angry at Sassoon for returning to war. Rivers thinks sadly that Craiglockhart has defeated Sassoon’s protest in a way the war never could. In his first couple weeks in London, Rivers visits another hospital to meet Dr. Yealland, a physician who also treats psychological ailments. Yealland is authoritative and his methodology is masculine and domineering—contrasting with Rivers’s nurturing style of therapy—which is put on display when Yealland “cures” a patient’s mutism by torturing him with an electrode for hours until the man forces himself to speak again. Rivers does not interfere, but the image haunts him long after and he has a nightmare about forcing a horse’s bit into Yealland’s patient’s mouth. While analyzing his dream, Rivers concludes that his patients’ debilitating symptoms—mutism, stammer, amnesia, and so on—are a form of unconscious protest their minds make against the war, and by treating them and sending them back to combat, Rivers is silencing their protest just as he silenced Sassoon’s protest.
Rivers returns to Craiglockhart to participate in Sassoon’s examination. To both of their great relief, Sassoon is pronounced fit for combat even though he won’t withdraw his declaration. As they say goodbye, Rivers reflects on how strange it is that Sassoon’s person and actions have fundamentally shifted Rivers’s own view of war and duty, leading him to think that regardless of the causes, war seems to inflict too much pain to be worthwhile, and any society that sacrifices its young men as soldiers does not deserve their loyalty.
