Currer is the slave of Thomas Jefferson. When he strikes up a sexual relationship with her, he grants her special favors so that she works as a laundress and pays him her wages. She is still a slave in the eyes of the law. Together they have two daughters -- Clotel and Althesa. Because Currer is nearly white already, her children can pass for white. According to the partus sequitur ventrem, however, they are legally considered black and slaves. When Jefferson dies, the entire family is sold to different masters.
Currer and Althesa work for a slave gang for some time until Currer is sold to a Mr. Peck. He's a preacher with a kind daughter. Currer and the girl strike up a friendship to the extent that the girl decides to advocate for Currer's freedom. Tragically Currer never lives to see her potential emancipation because she dies of yellow fever shortly afterwards.
Althesa is sold to Henry Morton a businessman from the North. The two of them fall in love, so he helps Althesa pass as a white woman. They get married and have two daughter -- Jane and Ellen. As white girls, they receive a good education and are somewhat spoiled by their father. Despite their marriage, Morton has not freed Althesa or their daughters, although he keeps that a secret from his wife. Eventually both parents die, so the girls are sold. Having never lived as slave in their lives, they do not adapt well at all. Ellen commits suicide after her master rapes her. And Jane wastes away and dies, having lost the will to survive.
On the other hand Clotel is purchased by a Mr. Horatio Green. He loves her and makes her his wife, although he cannot legally marry her for the same reasons Jefferson couldn't marry her mother. Together they have one daughter, Mary, whom they raise together. Somewhere down the line Green decides to become politically active and realizes the liability of having a black wife and child to his career. He marries a white woman and brings her home. Immediately after she learns of Clotel and Mary, this women sells Clotel and makes Mary their house slave.
In Mississippi, Clotel now works for a planter. She develops a close friendship to a fellow slave named William Because of her white skin, Clotel dresses up as a white man in a scheme to help both of them escape. They make it to Ohio before parting ways, William continuing on to Canada. Worried about her daughter, Clotel returns to Virginia to try and rescue her. Tragically she is captured and sold once more. She escapes at the market and leads her captors onto the Long Bridge. Desperate to escape her miserable fate, she jumps into the Potomac and drowns.
Meanwhile, Mary is adapting to her new life as her father's slave. Over time she grows fond of a slave named George who has landed himself in prison. She helps him escape one day by taking his place in disguise in the prison. He successfully escape. Mary, however, is sold to a French trader who takes her back to his homeland. Eventually he dies, but Mary is freed. She reunites with George in Dunkirk where they are married.
