Fifteen-year-old Amari laughs as her little brother, Kwasi, plays in a coconut tree. Kwasi teases Amari that her fiancé, Besa, is coming, and then he runs back to their village. Besa approaches and greets Amari warmly but says he’s concerned—he saw men with light skin coming to the village. Amari relays this to Mother and her friend Esi. Mother scolds Amari for being concerned about the visitors; she says it’s uncivilized to judge people on looks. The village prepares for a celebration as the white men and Ashanti warriors arrive. Amari thinks that they look dangerous, but she throws herself into preparations, listens happily to Father’s ceremonial story, and enjoys the drumming. Then, disaster strikes: the white men begin shooting and Ashanti warriors club down women and children. Amari and Kwasi try to run, but an Ashanti spears Kwasi. They capture Amari.
The Ashanti and the white men shackle Amari and the remaining villagers, all young people, and force them to march. As the days pass, many die. They finally reach a city on the coast, and once the white men separate the men from the women, they unshackle Amari and push her into a dark room. It smells of sweat, blood, and waste. Later, a woman named Afi helps Amari get food and explains that they’ll be sold and sent into the sea—she and Amari are slaves. Over the next few days, Amari’s captors sell her, brand her, and imprison her in a pen on the beach. After two meals, they load male slaves into small boats and ferry them out to a larger ship on the sea. Amari catches sight of Besa and cries, but Afi tells her to forget him. The female slaves are next. Two women jump into the water, but sharks eat them. The sailors lead the women past the men, who are stacked tightly on shelves, and chain the women in the hold. Hours later, they bring the women and children up to the deck. There’s no land in sight.
The journey is horrifying. Though on some nights a sailor named Bill teaches Amari English, sailors rape the women nightly. The sailors also force the slaves to dance every day for exercise. As Amari’s command of English grows, she learns that they’re heading for someplace called Carolina. When she sees the land, she’s shocked that it’s beautiful. Afi cautions her to look for the beauty when things are bad; she’ll survive that way. In the warehouse near the shore, Besa finds Amari and tells her to never forget him. Then, the slaves are shipped to Charles Town for auction. Amari is terrified and confused as white men strip her, bind her wrists and ankles, and slather her in oil.
A white girl named Polly is at the slave auction. She’s uninterested since she doesn’t like Black people, so she reads her certificate of indenture instead. It reads that Polly will serve Mr. Derby for 14 years. Polly sees Mr. Derby purchase a slave girl, Amari, and watches her struggle when Mr. Derby tries to lead her away from the older woman next to her. Polly wonders if Black people actually have feelings. While Mr. Derby purchases Amari, his son, Clay, arrives whipping a well-dressed slave named Noah. Polly asks why Clay beats Noah—she doesn’t think that slaves need to be beaten, even if she doesn’t like them. Clay insists that it’s how he shows he cares and tells Polly that if she remains so feisty, Mr. Derby might whip her. Mr. Derby returns, ushers Polly into the back of the wagon, and begins the long journey home. On the way, he tells Clay that Amari is his birthday present. Clay decides to call Amari Myna, since she belongs to him. They discuss that while white women should be treated delicately, Black women are different—and having sex with them shows them who’s boss. When they reach the plantation, Polly is aghast and upset when Mr. Derby tells her it’s her job to “civilize” Amari. She expected to serve at the house and learn to be a lady—but instead, she’s stuck in a slave shack.
Amari and Polly meet Teenie, the slave cook; her son, Tidbit; and his dog, Hushpuppy. Teenie feeds the girls and listens to Polly’s story: Polly’s father was an indentured servant, but both he and Polly’s mother died of smallpox. Polly’s indenture is twice as long as usual, since she has to pay her parents’ debts. Teenie reminds Polly that someday, she’ll get to be free. That night, Clay calls for Amari; he calls her often over the next few months. Amari hates him. Meanwhile, Amari learns English and helps Teenie in the kitchen. Teenie’s mother came from Africa; one day, as she comforts Amari, she tells her that as long as she remembers Africa and her parents, they’re never gone. After an especially bad night with Clay, Amari asks Teenie if she has herbs that could kill her. Teenie insists that Amari must live and shows her the kente cloth that Teenie’s mother managed to hang onto all the way from Africa. A week later, while Amari, Polly, and Tidbit pick peaches for a pie, Amari and Polly talk about what they’ve lost.
Mrs. Derby, Mr. Derby’s second wife, is lovely, caring, and pregnant. She comes daily to Teenie’s kitchen to plan meals—but Teenie cooks whatever she wants anyway. Mrs. Derby looks at Amari with compassion, and once, she even apologizes for Clay’s behavior. Amari listens to Teenie and Lena, a house slave, discuss Mrs. Derby. Lena thinks that Mrs. Derby’s life is idyllic, but Teenie insists that she is almost a slave given how controlling Mr. Derby is. Mr. Derby married her because she’s young and rich and came with land. Meanwhile, Polly never loses sight of her dream of working in the house. As Amari settles in, Polly realizes that this could be a real possibility soon. Teenie sends Polly, Amari, and Tidbit to the rice fields with food and water for the slaves there. At the fields, Cato, the oldest slave on the plantation, says that Amari will be in the rice fields as soon as Clay gets tired of her—and when Tidbit is old enough, he’ll work in the fields too. In the fields, slaves rarely survive more than five years because of the snakes, alligators, malaria, and cholera. Both Polly and Amari are aghast. Just then, a woman named Hildy screams—a snake bit her. Other slaves drag her to dry land, but they have to get back to work. She’ll die by nightfall.
Back at the kitchen, Teenie says that she has an idea to keep Amari from the fields: one of the house slaves is Hildy’s daughter, and Amari and Polly will take her place at dinner. Polly is thrilled. As dinner progresses, Polly realizes that Mrs. Derby is deeply unhappy and powerless. After dinner, Mr. Derby trips Amari while she’s carrying a pie. The pie goes all over the carpet. He whips Amari until Mrs. Derby makes him stop, and Amari spends three weeks recovering from the ordeal. Polly, Teenie, and Mrs. Derby nurse her. When she’s better, she tries to lay low in the kitchen—Mr. Derby insisted she go to the fields after the dining room debacle. She feels like her spirit is dead. To make matters even worse, Clay comes into the kitchen one afternoon to fetch Tidbit and use him as alligator bait. He makes Amari come so he can show her off to his friends. Amari cannot believe their cruelty.
Several weeks later, Mr. Derby bursts into the kitchen. Mrs. Derby is in labor, and he can’t find any of the house slaves. He runs to the neighboring plantation and sends Amari and Polly to help his wife. Amari easily delivers Mrs. Derby’s baby—but the baby is Black. Mrs. Derby begs for the girls to save her baby. She believes her husband will kill her, the baby, and Noah, the baby’s father. With Teenie’s help, they get the baby to a slave woman named Sara Jane. Though they tell Mr. Derby that the baby was stillborn, he insists that the doctor is on his way and will need to examine the body. Polly runs to meet Noah and Dr. Hoskins on the road, but Dr. Hoskins refuses to turn around—and when he arrives, Mr. Derby realizes that his slaves and his wife are hiding something. While Dr. Hoskins and Mr. Derby are inside, Teenie tells Noah the news, and Noah shares that he loves Mrs. Derby. Clay arrives with the baby as Mr. Derby drags Mrs. Derby outside. He makes her watch as he shoots Noah and the baby. Then, he locks Amari, Polly, Teenie, and Tidbit in the smokehouse and announces that he’s selling the girls and Tidbit. That night, Cato tells the captives that Dr. Hoskins doesn’t believe in slavery. He’ll let them escape, and then they should head south to Fort Mose. He follows Teenie’s instructions to poison Clay and make him ill so that he can’t accompany the doctor. Teenie gives Tidbit her mother’s kente cloth and wails as the wagon pulls out. Mr. Derby whips her.
An hour from the plantation, Dr. Hoskins says that he’s ashamed. He gives Amari, Polly, and Tidbit food, money, and a gun and sends them into the woods. Hushpuppy soon catches up to them. They hurry night and day for several days but have to stop when Amari gathers fruits that make them vomit. Amari is concerned when she seems not to fully recover from the ordeal. She’s nauseous and dizzy. Occasionally, Amari catches fish or they’re able to find crayfish in rivers they cross. One evening, Tidbit wails that Hushpuppy is gone. It begins to rain, and late in the night, they discover a cave and build a fire. The girls are terrified when they notice an animal lurking outside, but it turns out to be Hushpuppy with a fat rabbit. A few days later, Clay reaches out and snatches Amari. He ties her, tells her that his father died, and wonders how to punish her for running away. Polly shoots Clay in the head, just grazing his temple and knocking him out. The girls tie him up, and as Clay wakes up, he comes face to face with a rattlesnake. They leave him to his fate.
Not long after, the travelers meet a boy named Nathan. He confirms that Fort Mose is real and hides them in his father’s barn; but Amari, Polly, and Tidbit have to hide in a swamp when Nathan’s father discovers them. Not long after that, a woman named Fiona finds them in her husband’s hunting shelter. Though she owns slaves and believes that slavery is okay, she’s excited to be able to make her own decision for once and has one of her slaves hitch up a wagon for the runaways. The slave is Besa, but his spirit is broken. He refuses to let Amari touch him and insists that he doesn’t have dreams anymore. Several days later, they come across a Spanish soldier. Though he pretends to buy Polly’s story—that she’s heading home to her father—he gives them valuable information about Fort Mose and where to cross the river into Spanish Florida. Not long after, they reach the river and ride the horse across. After a night of sleep, they ride toward Fort Mose. Tidbit still misses Teenie, but asks Amari to be his mother now. Amari agrees. On the outskirts of the city, a woman named Inez feeds the runaways, assures them that they’re safe, and introduces them to Captain Menendez. He’s an escaped slave, and he decides that Amari will weave and Polly will teach children to read.
Inez takes Amari to show her where she’ll live. They discuss the difficulties of slavery and Inez asks how Amari has been feeling. Inez insists that Amari isn’t unwell—she’s pregnant. Amari is distraught, but Inez insists that Amari already loves her baby and needs to tell her baby all her stories. She leaves Amari alone. Amari vows to never think of Clay and realizes that her baby holds the spirits of her mother, her father, Kwasi, and all her murdered villagers. She looks at the copper sun and feels like she’s found a home again.
