The first section of The Vegetarian is narrated by a man named Mr. Cheong, who lives with his wife, Yeong-hye, in Seoul, South Korea. Their relationship is normal and unremarkable. Yeong-hye is a woman of few words, cooks and keeps the house, and reads as her sole hobby. The only strange thing about her is that she sometimes does not like wearing a bra, and despite Mr. Cheong’s insistence that she wear one, she tells him that bras make her uncomfortable.
The blandness of their lives changes abruptly when one day, Yeong-hye wakes up in the middle of the night from a graphic dream in which she is violently killing and eating an animal, pushing raw meat into her mouth. Haunted by this dream, she throws away all the meat in the house. Mr. Cheong is aggravated by this behavior, and becomes even more frustrated when she refuses to cook meat for him anymore. Mr. Cheong views this as a selfish and disobedient act, and calls her insane. He is particularly confused because she had always been skillful at cooking meat.
Over the next few months, Yeong-hye loses weight and starts refusing to have sex with her husband, explaining that his body “smells of meat.” She becomes unable to sleep. One evening, the couple has dinner with several of Mr. Cheong’s co-workers, including his boss. Yeong-hye does not wear a bra to the dinner, attracting the notice of his co-workers. She also refuses to eat the meat served at dinner, and thus ends up not being able to enjoy most of the 12 courses served family-style. The others comment critically on her vegetarianism, and gradually stop talking to her at dinner. Mr. Cheong is appalled at his wife’s behavior.
Mr. Cheong decides to call Yeong-hye’s mother and her sister In-hye in the hopes that they can convince Yeong-hye to give up her vegetarianism. They are equally shocked at Yeong-hye’s decision to disobey her husband but are unable to convince her to eat meat again. Mr. Cheong also becomes frustrated with Yeong-hye’s abstention from sex, and he pins her down and rapes her on several occasions. Yeong-hye also begins to take her clothes off when she is alone at home, cooking naked. When he asks why she does this, she only tells him that she is hot.
Yeong-hye continues to be haunted by nightmares wherein she is violent and murderous, and continues to lose weight. Her family (including her mother, father, In-hye, In-hye’s husband, and her brother Yeong-ho) gather together for a meal at In-hye’s apartment. Yeong-hye’s mother tries to get Yeong-hye to eat meat, even holding pieces of pork up to her lips. When this fails, her father becomes outraged and tells Mr. Cheong and Yeong-ho to hold Yeong-hye’s arms; he then slaps her and jams a piece of pork into her mouth. Yeong-hye immediately spits out the pork and, in desperation, cuts her wrist open with a knife. Mr. Cheong and Yeong-hye’s brother-in-law immediately take her to the hospital. At the hospital, Yeong-hye’s wound is stitched up, but before she is discharged, she disappears from her room. She is found on a bench having removed her hospital gown, with a dead white bird with bloody bite marks on it in her hand.
The second section, “Mongolian Mark,” is narrated from the perspective of Yeong-hye’s brother-in-law (In-hye’s husband), two years after the first section. The brother-in-law is a video artist; his wife, the primary breadwinner in their home, is the manager of a cosmetics store. The brother-in-law and In-hye’s marriage is strained, and he is more attracted to Yeong-hye. Recently, the brother-in-law has become obsessed with images of men and women covered in painted flowers having sex. This obsession began when In-hye (while giving a bath to their toddler Ji-woo) mentioned that Yeong-hye still has a Mongolian mark. The brother-in-law imagines the two of them having sex together and longs to film it.
After being discharged from the hospital, Yeong-hye lived with In-hye and the brother-in-law for a time due to the fact that Mr. Cheong left her, but she now lives alone. The brother-in-law visits Yeong-hye and asks her if she would model for him—he explains he wants to paint her body with flowers and film her naked. She tacitly agrees, and the brother-in-law becomes filled with lust. He is overcome by desire and has sex with In-hye for the first time in months. He puts his hand over her mouth and imagines she is Yeong-hye. When he is finished, she cries, but he falls quickly into sleep and they do not address this incident afterward.
Yeong-hye comes to the brother-in-law’s studio, where she calmly undresses. He paints huge flowers on her body and films her in different poses. Afterward, they go out to dinner. He asks her why she doesn’t eat meat, but she says that he wouldn’t understand. That evening, the brother-in-law returns to his film studio, forcing In-hye to come home early to watch Ji-woo. There, he reviews the tapes and cuts them into a video, but he knows that he wants to film more. He asks a fellow artist friend, J, to model with Yeong-hye. He calls Yeong-hye, who has not washed off the paint, and asks her to come back and model again, this time with another man. She agrees.
The next day, J and Yeong-hye come to the studio. The brother-in-law paints J in flowers, and then he and Yeong-hye start to pose, with Yeong-hye doing things like craning her neck around J’s, stroking him, and straddling him without being asked. J becomes aroused, and the brother-in-law asks if they would have sex for real. J immediately refuses, and leaves shortly after. As Yeong-hye dresses, she confesses that she wanted to have sex with J because of the flowers on his body. The brother-in-law then drives away, gets another artist friend to paint flowers on him, and returns to the studio where Yeong-hye is waiting. The brother-in-law immediately lays Yeong-hye down and aggressively has sex with her, forgetting his camcorder. When they are finished, Yeong-hye strokes the flowers on his chest, and he turns the camera on and films himself having sex with her from behind. Yeong-hye bursts into tears, and he switches off the camera. In their final minutes of sex, she yells at him to stop. Afterward, the two fall asleep in the studio together.
When the brother-in-law wakes up, Yeong-hye is still asleep, but the camera is gone. When he goes to search for it, he finds In-hye at the studio. She tells him that she had come to look for him, had watched the film, and that she called emergency services on him. Just then, Yeong-hye wakes up and goes over to the veranda, showing her naked body to the sun. The brother-in-law thinks about throwing himself over the railing.
The third section, “Flaming Trees,” is narrated by In-hye, two years later. Yeong-hye now lives in a psychiatric hospital and is refusing to eat entirely. A doctor tells In-hye that if she cannot get Yeong-hye to eat, they will try a method of getting her to eat that they have tried before: inserting a tube into her nose to feed her gruel. If this does not work, she will have to be transferred to a general hospital for a complicated surgery that will allow them to hook an IV up to her arteries to keep her alive.
In-hye drifts in and out of several memories from the last two years. She describes an incident in which Yeong-hye had run away and had been found in the mountains, acting like a tree. Afterwards, Yeong-hye had told her that all of the trees were like brothers and sisters to her. She tells In-hye that she doesn’t need to eat anymore—she only needs sunlight and water. On another visit, In-hye had asked Yeong-hye if she thinks she’s become a tree, asking her how a tree could talk. Yeong-hye agrees with this logic, saying soon her thoughts and words would disappear.
In-hye also thinks about her husband: how she had wanted to take care of him, but was never fully sure that she loved him and was never sure that he loved her. She knew, instead, that he was in love with his work. She always thought he was incomprehensible to her. After she called the police on him, he had tried to throw himself over the railing, but was rescued by a paramedic. He then had to prove that he was not mentally ill, and had been held in prison for several months. Afterwards, he went into hiding, and In-hye never saw him again, though he called once to inquire about Ji-woo.
In-hye feels guilty about Yeong-hye’s condition and wonders what she could have done to prevent it. But In-hye is also in some ways jealous of Yeong-hye’s ability to simply “shuck off social constraints.” She thinks that Ji-woo is the only thing that is keeping her tethered to reality. Even when she was still with her husband, she thought often of ways to harm herself or kill herself, and once walked into the mountains, intending to completely abandon her family, but decided to return.
In the present, In-hye is unable to convince Yeong-hye to eat. Yeong-hye is then taken to another ward and the doctor tries to insert the tube into her nose. Yeong-hye grows upset, saying that she doesn’t want to eat, and tries to resist their efforts. In-hye watches as they successfully insert the tube, but when they pull out a tranquilizer so that Yeong-hye can’t throw up the food, In-hye runs into the room and bites a caregiver in the ward who tries to hold her back. Yeong-hye struggles, then throws up blood and has to be transferred to a general hospital immediately. Before they leave, In-hye thinks, “it’s your body, you can treat it however you please.” In the ambulance on the way to the general hospital, In-hye confesses to Yeong-hye that she has dreams, too, but that at some point a person has to wake up. As they drive, In-hye sees a forest of trees glinting in the sunlight. She looks at them “as if waiting for an answer. As if protesting against something.”
