As an old woman, Aminata Diallo is brought to London, England, in 1802, by abolitionists who are petitioning to end the slave trade. As she awaits an audience with King George, she recounts her remarkable life on paper, beginning with her life in Bayo, in western Africa, prior to being abducted from her family at age 11, seeing the death of her mother and father, and being marched in a coffle of captives to the coast along with others from her village. Chekura, a boy of similar age who assists the slave catchers, is at the last minute abducted himself and forced to join Aminata on the slave ship.
Despite suffering humiliation, witnessing atrocities, enduring squalor and languishing in starvation, Aminata survives the passage to America because she is able to apply the knowledge and skills passed on to her by her parents, especially the ability to “catch” babies and to understand some African languages. In South Carolina, Aminata is auctioned off to an indigo plantation, along with a man from her village who has lost his senses during the ocean crossing.
She learns the language of the “buckra” through the teachings of Georgia, an American-born slave, as well as from Mamed, the overseer of the plantation. Daily, Aminata must navigate the new dangers of disease and the eye of the plantation master while she searches for a way to return to her homeland. As she carries Chekura’s child, she is warned that Master Appleby could take it away at any time. Sure enough, at ten months, Aminata’s son, Mamadu, is sold by Appleby and Chekura also disappears. Stricken with grief, Aminata falls into a depression and refuses to work on the plantation.
Appleby sells her to Solomon Lindo, the indigo inspector of the region, and she departs for a new life in Charles Town where Lindo promises to treat her as a “servant” rather than as a “slave” in that she works for wage and pays rent to Lindo. During rioting in New York City that coincides with the outbreak of the American Revolutionary War, Aminata is presented with an opportunity to escape and does so, while Lindo is forced to flee back to the Carolinas. Aminata quickly makes new friends and connections and supports herself by catching babies and working at a tavern, all the while helping others by teaching them how to read and write.
Following the surrender of the British, former slaves who have worked for one year or more behind the lines for the British are offered asylum in Nova Scotia. These people’s names are recorded in a ledger called The Book of Negroes, penned in part by Aminata because of her knowledge of many languages. Aminata and Chekura reunite and are given passage aboard the ship Joseph, but Appleby returns for one final act of vengeance against Aminata: he makes a claim to her, separating her from Chekura once more.
While Chekura continues to Nova Scotia, Aminata must stand trial, and it is Solomon Lindo who ends up setting her free. Aminata lands in Shelburne, Nova Scotia, on the last Loyalist ship, and she has to use her talents as a baby catcher, reader and teacher once again to survive, for the sake of herself and her unborn child, as she prepares for the journey to reunite with Chekura in Annapolis Royal. However, her inquiries come up empty. May, their three-year-old child, is abducted by the Witherspoons, a white couple who had befriended Aminata, and Aminata returns to a life without hope.
When the opportunity arises for Aminata to cross the ocean again to begin a colony in Sierra Leone, Africa, she is shocked to learn of Chekura’s death and decides to make the journey to her homeland. The struggle to maintain the colony of Freetown under the control of the Sierra Leone Company is complicated by its proximity to Bance Island and the slave trade. Relations with the local Temne are strained, and tempers flare when slave coffles are marched directly in front of Freetown. Longing to see her beloved Bayo village, Aminata agrees to travel back to Bance Island to secure passage into the interior.
However, one month into her journey inland, she learns of the betrayal that she is to be sold back into slavery; she flees for days until she finds sanctuary in a village. Realizing that she will never return to her true home, she leaves for London to join the abolitionists to end slavery. She writes an account of her life that is shared in Parliament, and she meets with King George III and Queen Charlotte Sophia. Because of the attention from the newspapers, Aminata’s long-lost daughter, May, finds her after an eighteen-year separation and takes care of her in her old age as the struggle to end slavery continues in Parliament.