The Underground Railroad tells the story of Cora, a teenager who runs away from the Georgia plantation where she and her family have been slaves for three generations. Cora’s grandmother Ajarry was brought to the United States from Africa on a slave ship and died after decades working in the fields of the Randall plantation. Cora’s mother, Mabel, ran away, abandoning Cora, and everywhere she goes, Cora looks for answers about her mother’s fate. Left without her mother to protect her, Cora is mistreated by the other slaves, although she shows her fierce nature, challenging a slave named Blake who tries to take her garden plot, and protecting a young slave from the cruel master Terrance. Finally, she escapes with another slave, Caesar. They make it to a stop on the underground railroad, but not before some locals try to capture them and Cora kills a teenage white boy in order to get away.
The underground railroad, in this novel, is an actual railroad with stations below farms and houses. The first train takes Cora and Caesar to South Carolina, where they are able to live more like free people. The move from Georgia to South Carolina sets the pattern of telling a series of stories about Black experience not just during slavery but throughout American history.
In South Carolina, Cora and Caesar are met by Sam, a cheerful white station agent who will be their contact during their stay and assigns them new identities. Here, Cora and Caesar are housed, fed, and given jobs. Life is so much better than on the plantation, they are able to ignore things that don’t seem fair. After working as a maid, Cora is sent to work as a “type” in a museum that puts forward a very false, positive version of African and slave life. One night, Cora and Caesar learn from Sam that the hospital they thought was helping them with free medical care is actually conducting government experiments to kill off and sterilize Black people. Then they learn that the slave catcher, Ridgeway, has arrived in search of them. Cora escapes to the underground railroad platform, but Caesar is left behind, and Sam’s house is burned to the ground.
Cora’s next stop is North Carolina, where the situation for Blacks, free or fugitive, is much worse. Cora is taken to the home of the reluctant station agent Martin Wells and his wife Edith, who is very upset by Cora’s presence. Cora lives in a small hiding space in the Wells’ attic, where she sees a horrible spectacle take place every Friday night on the town square. North Carolina has worked to expel or kill all Blacks in the state, and Friday Festivals are a weekly display of racist propaganda ending with the hanging of a Black person, a grisly act in which the whole town participates. As time goes by, Cora improves her reading in the attic room, but there is no way out for her. Finally, Cora falls ill and has to be cared for in the Wells’ home. Their maid Fiona informs on them, and that Friday night a group of night riders searches the house, finding Cora. With the patrollers is the slave catcher, Ridgeway, who chains Cora to his wagon and takes her with him, while Edith and Martin Wells are hanged from the oak tree.
Tennessee is even worse than North Carolina. Cora is taken through the state by Ridgeway and his two companions, a violent man named Boseman who wears a necklace of human ears, and an odd Black boy named Homer. They also have picked up a runaway named Jasper who constantly sings hymns. The first half of Tennessee they travel through is completely blackened by wildfires. Even the white settlers have been displaced. Halfway into their journey, annoyed by his singing, Ridgeway shoots Jasper in the face. They drive out of the fires, but the next series of towns are in quarantine due to a yellow fever outbreak. Finally, they stop in a town where Cora is acknowledged by a young Black man wearing glasses. After Ridgeway takes Cora to dinner and tells her about Caesar’s death, they stop for the night in the woods outside of town. Boseman tries to rape Cora and Ridgeway punches him. At that instant, the man wearing glasses appears with two others, all armed. One shoots Boseman, another chases Homer, and the man with glasses fights with Ridgeway. Cora jumps on Ridgeway’s back and they subdue him. Homer gets away, Ridgeway is chained to his own wagon, and Cora is rescued.
The man with glasses is Royal, a conductor on the underground railroad, who takes Cora to Valentine farm in Indiana. There she truly lives as a free woman, attending school and contributing to the life of the large farm occupied by free and escaped Blacks. She and Royal begin a romance, and she also becomes close to her housemate Sybil and Sybil’s daughter, Molly. Valentine farm was founded by a light-skinned Black man named John Valentine, who often passed for white, and his wife Gloria. Every Saturday night on the farm there is a big feast followed by lectures, poetry readings, singing, and dancing. However, hostility from the nearby white community is growing as the whites feel threatened by the size of the Black community.
Royal takes Cora on a buggy ride and picnic and shows her an abandoned house with an underground railroad station beneath it. It is too small for an actual train and just has a handcar and a narrow tunnel. No one knows where it goes. The experience makes Cora uneasy, since she wants to settle on the Valentine farm and not be forced to flee on the underground railroad anymore. Sam appears on Valentine farm on his way to California and tells Cora that Terrance Randall is dead and no one is looking for her anymore.
On the night that two speakers, Mingo and Lander, debate the future of Valentine farm, a white mob arrives, killing Lander and Royal and many others. They burn down the buildings while the residents flee. Later, people will only know about the farm and the massacre because survivors tell the story to their descendants. Cora is captured by Ridgeway and Homer, who order her to take them to the underground railroad station.
Before the book ends, we learn that Cora’s mother Mabel never made it farther than the swamp bordering the Randall plantation. As she was returning to take care of Cora, she was bitten by a poisonous snake and her body sunk into the swamp.
Cora takes Ridgeway to the abandoned railroad station, where she pulls him down the steps and he is mortally wounded. Homer tends to Ridgeway while Cora pumps the handcar down the tunnel. She travels for miles, then walks until she emerges into daylight. On the trail, she encounters three covered wagons, the last one driven by an older Black man named Ollie. He feeds her and tells her he is going to St. Louis to join a wagon train to California. She joins him and wonders about his story, which he will certainly tell her on the way.