Letters from a Slave Girl: The Story of Harriet Jacobs is a fictional biography by Mary E. Lyons. In this novel, Mary Lyons has taken her research into the true life story of Harriet Jacobs and told it through a set of fictional letters she imagines Harriet Jacobs might have written during her days as a slave and later as a fugitive slave. Harriet writes letters to those who have touched her life and then left it, either through death or escape to freedom. Letters from a Slave Girl is a touching true story of life in slavery from a woman's point of view, a narrative that has often been overlooked in history.

Harriet is eleven when she begins writing letters to her mother. The letters begin as Harriet's first owner, Margaret Horniblow, has died. Harriet hopes that Margaret will free her in her will because of a promise Margaret once made to Harriet's own mother on her death bed. However, Harriet is disappointed to learn that Margaret has left her to her three year old niece, Mary Matilda. This means that Harriet will have to go live with Mary Matilda's family, including her cruel father, Dr. Norcom.

In letters to her father, Harriet describes life at the Norcom house, how hard the work can be and how cruel Dr. Norcom's wife often is toward Harriet. At the same time, Harriet worries about her brother John. John has never accepted his slavery well and he grows angrier and angrier each day he is forced to serve Dr. Norcom's son, James Jr. At the same time, Harriet has become aware of an uncomfortable interest Dr. Norcom has begun to take in her. As Dr. Norcom's attentions become more and more insistent, Harriet turns to a kind white man who has been a friend of her grandmother's for many years. Harriet gives herself to this kinder man, Samuel Sawyer, in the hopes that it will dissuade Dr. Norcom from his interest in her. With advent of a pregnancy, Harriet does win a temporary reprieve from Dr. Norcom's attentions.

After the birth of her first child, Harriet goes to live with her grandmother because of Mrs. Norcom's outrage at her pregnancy. Harriet lives there for many years, even after the birth of a second child. However, Dr. Norcom is growing impatient and tells Harriet that either she move into a cottage he has had built for her or he will send her to live on his son's plantation and sell her children. Harriet chooses the plantation, but decides to run away rather than allow Dr. Norcom to sell her children. Harriet runs to a friend and hides in her home for some weeks, then is moved to several other places until finally ending up in a tiny garret cut above the store room in her grandmother's home. Dr. Norcom, frustrated with his inability to find Harriet, arrests her brother, aunt, and children. Harriet refuses to expose her hiding place and Dr. Norcom runs short of money, finally selling John and the children to Sawyer, unaware he has just played into Harriet's hands.

Harriet lives in the garret for seven years, watching her children grow up in the yard below her. After a time, Harriet begins sending letters to Dr. Norcom, convincing him that she is living in New York. With each passing year Harriet feels safer and safer, but still cannot expose herself for fear of hurting her free grandmother or uncle. Harriet lives each day hoping Samuel Sawyer will free her children, but instead he takes their daughter and gives her to a cousin in New York as a servant.

Harriet has the chance to escape on a ship going north, but she passes it up due to her grandmother's fear. However, when a nosy neighbor spots her in the store room of her grandmother's house, Harriet is forced to flee. Harriet arrives in Philadelphia and quickly makes her way to New York to reunite with her daughter. Over time, Harriet and her children are reunited for a brief time. Over the next fifty years, Harriet devotes herself to helping fugitive slaves and educating former slaves. Harriet also publishes an autobiography that is the first of its kind to address the sexual abuse that often impacted female slaves.