Aminata Diallo, the daughter of a jeweller and a midwife, is kidnapped at the age of 11 from her village Bayo, near Segu in West Africa and forced to walk for days to the sea in a coffle with hundreds of strangers and a handful of people from her village. After several horrific months of voyage across the Atlantic Ocean she arrives in South Carolina where she begins a new life as a slave and her name is anglicized to Meena Dee. Because of her youth and intelligence she quickly learns English. A fellow slave named Mamed secretly teaches her to read and write after learning that she is Muslim, a religion she shares with her now-deceased African mother.
As a teenager Aminata privately marries Chekura a young boy who works with her captors then sold into Slavery with her both making the crossing to America together.The two conceive a son whom Animata names Mamadu, but the child is sold, as well as Aminata separately, Aminata to a Jewish man named Solomon Lindo who moves her to Charles Town. During the following 13 years she is only able to see Chekura once.
Aminata grows close to Lindo and his wife, who allow her to read and write openly. However Solomon also forces Aminata to pay him a part of any money that she earns through midwifery. After his wife dies of the pox Lindo takes Aminata to New York.
During the rioting at the outbreak of the American Revolutionary War Aminata is able to escape from Lindo. During this time Aminata works as a midwife and teacher, helping other black people to learn how to read. Proving that she served the British in the American Revolutionary War her name is entered in the historic "Book of Negroes", an actual historical document that is an archive of freed African American slaves who requested permission to leave the United States in order to resettle in Nova Scotia. Because of her ability to read and write as well as her fluency in two African languages, Aminata is also hired to help record names in the book. While doing this work she is reunited for a few months with Chekura, who also served the British and plans to resettle in Nova Scotia with Aminata. They conceive a second child, a girl, whom Aminata names May but the two are separated again just before they depart for Nova Scotia.
In Nova Scotia, Aminata arrives in Shelburne and begins to work in the black community of Birchtown. She experiences the hardships of the Black Loyalists who endure cold winters, sickness and the hostility of white Loyalists including the attacks of the Shelburne Riots. Aminata tries multiple times to locate her husband, who was sent ahead of her to Annapolis Royal, but is unable to encounter any news of him. It later emerges he died during the crossing.
Years later Aminata encounters John Clarkson, a young British naval officer recruiting black settlers to move from Nova Scotia to Sierra Leone. Through Clarkson Aminata learns that the ship carrying her husband to Nova Scotia was sent off course to Bermuda during a storm. Through an initiative headed by Clarkson, Aminata, along with hundreds of other Birchtown blacks, decide to relocate to Sierra Leone with the promise of a better life than what they were given in Nova Scotia.
Aminata eventually returns to Africa, passing along the way, ships carrying thousands of slaves bound for America. In Sierra Leone, they attempt to establish Freetown despite the strict rules of the British. Longing to return to her village in the interior of Africa, Aminata pays a slave trader to take her there. When she discovers she cannot trust him, she realizes that what is more important than returning home is to help free her people. As an old woman, she finds herself crossing the ocean one more time to England to present the account of her life so it may help abolish the slave trade. She is eventually reunited with her nearly twenty-year-old daughter May, who cares for her until her dying day.