In Gwangju, 1980, a middle school student named Dong-ho labors alongside a civilian militia (consisting of other students and workers) to deal with the bodies of people killed by soldiers. Dong-ho intends to find his missing friend, Jeong-dae, who is later revealed to be dead. When those working to process the bodies run out of space at the Provincial Office, they transform a gymnasium into a morgue. Gwangju citizens come in search of their missing loved ones. Dong-ho volunteers alongside a pair of women named Eun-sook and Seon-ju, who all answer to a man named Jin-su. They receive word of an imminent military assault on the city. Although he is warned by friends and family to return home, Dong-jo decides to stay, resulting in his death.
The second chapter is written from the perspective of Jeong-dae, who witnesses his body after his death. Soldiers gather the bodies of the civilians they killed and transport them to a remote clearing where they are left to rot. Eventually, Jeong-dae senses the presence of other souls but remains unable to communicate with them. Gradually, the revelation hits that his sister is among the dead. When the soldiers set the pile of bodies on fire, the tether between Jeong-dae's body and soul loosens. He resolves to find Dong-ho. At the end of the chapter, Jeong-dae feels the impact of his best friend's death as soldiers overtake the Provincial Office.
The next chapter takes place five years after the initial chapters and follows Eun-sook, who works as an editor at a publishing office. The police bring her in for questioning after she is seen meeting with a controversial translator. Eun-sook struggles to forget the punishment the interrogator dealt to her, which consisted of seven hard slaps across her face. The incident left her face swollen and smeared with blood. She goes to the censor's office to retrieve the manuscript proofs of a collection of plays only to discover that the censors have severely redacted the work. Despite not being able to publish the play, the playwright opts to follow through with the performance by having the actors speak their lines in incomprehensible ways. Eun-sook knows the lines since she worked as the editor. Watching the play overwhelms her with grief for Dong-ho.
In Chapter 4, an unidentified prisoner jailed for participating in the uprising gives an account of the various tortures he and the other prisoners endured. He addresses a professor who wants the prisoner to divulge his experiences so he can use them as material for the professsor's work. In prison, Jin-su suffers extra at the hands of the guards due to his more feminine demeanor. After both are released, the narrator bumps into Jin-su and they commiserate over the difficulties of adjusting to life after incarceration. They both deal with PTSD following the military crackdown on the uprising. These sporadic encounters between the narrator and Jin-su continue over several years until Jin-su commits suicide. The chapter ends with the narrator telling the professor he has no answer as to why such horrible things happen. He also emphasizes that he remembers the humanity of every single person he meets.
In 2002, Seon-ju (who worked alongside Eun-sook and Dong-ho during the Uprising) works as an environmental activist transcribing reports, trials, and testimonies. The same professor who previously reached out to the former prisoner in Chapter 4 also contacts Seon-ju. The professor (named Yoon) asks her to contribute her testimony on her experience during the Gwangju Uprising and its aftermath since he intends to expand his dissertation into a book. At the same time, Seon-ju considers visiting her old mentor Seong-hee, a famous labor organizer who is now in the hospital. Seon-ju ultimately decides not to share her experience, which includes brutal sexual assault. At the end of the chapter, she feels Dong-ho's presence as she enters the hospital to visit Seong-hee.
In Chapter 6, Dong-ho's mother shares how she still deals with grief and guilt over her son's death. She imagines seeing Dong-ho on the street. Even years later, she feels responsible for not preventing her son's death and the subsequent fallout between her other sons. The loss of Dong-ho imploded the entire family dynamic, but Dong-ho's mother stepped up in activist circles after getting to know other grieving parents whose children were killed in the Gwangju Uprising. Once her husband dies, however, she bitterly loses her drive to participate in the protests. Years pass, and Dong-ho's mother suffers in every season. She remembers Dong-ho as a baby and later as a young boy who liked writing poems and who always encouraged her to walk in the sun where the flowers bloom.
In the epilogue, author Han Kang speaks in the persona of a writer in order to share the stimulus behind the novel. When she was nine years old, the writer's family moved from Gwangju to the outskirts of Seoul. A real boy named Dong-ho and his family moved into the writer's family's hanok in Gwangju. The writer overheard snippets of conversation between the adults in her family regarding Gwangju. After looking through a hidden photo chapbook showcasing the brutal way soldiers treated civilians, the writer experienced a loss of innocence that completely shook her faith in humanity. As an adult, the writer researches the Gwangju Uprising and returns to Gwangju to physically spend time in the place where these historical events occurred. She contacts Dong-ho's brother to ask for permission to write a novel in which Dong-ho is a central character. The book ends with the writer lighting a candle at Dong-ho's grave.
