Isabel
She's the protagonist of the story. A young orphan, she is responsible for watching over her little sister. Isabel and Ruth are slaves. After being sold after the death of her beloved mistress, the girls suffer from all kinds of abuse at the hands of their new owners, the Locktons. Through it all, Isabel makes her and her sister's safety her top priority, working with the patriots as a spy among her British-sympathizing masters in exchange for the promise of freedom. She persists in her goal of freedom despite her sister being sold, being loaned out to a new mistress, a fire which consumes most of NYC, and repeated failures in her espionage work. Although she doesn't personally care about the revolution, Isabel sympathizes with the patriots because of her dear friend Curzon, a fellow slave who belongs to the cause.
Ruth
Ruth is a few years younger than Isabel. Just a child, she is less equipped to be successful in the harsh environment of slavery. When she starts to have seizures, she's accused of demonic possession by her mistress, Madam Lockton and sold. It's later revealed that she was actually transferred to a different property of the Locktons in Charleston.
Curzon
He's a slave at a neighboring estate to the Locktons. When he meets Isabel, he immediately strikes up a friendship. He convinces her to work as a spy, assuring her that it is the best way to gain her and her sister's freedom. After the British regain the city, he winds up in prison with all the other patriots except he's abused for being a slave. He becomes deathly ill, and starving but is fortunately rescued by Isabel's quick thinking. When the two make it to New Jersey, he agrees to stay with Isabel and help her free her sister.
Miss Mary Finch
She was the girls' kindly first owner. She always cared for the girls, never mistreating them. After her death, the girls expect to be freed as she had promised in her will, but her brother disrespects her final wishes in the will, and sells them to the Locktons.
Elihu Lockton
He's a wealthy British merchant who despises the patriots. He engages in a bunch of nefarious schemes to overthrow them, donating his wealth, influence, and other resources to the cause. Eventually he must escape to England permanently in order to avoid arrest thanks to Isabel's spy work.
"Madam" Anne Lockton
She's a cruel mistress who treats her slaves like animals. Recognizing the strong bond between the sisters, she keeps Ruth with her at all times in order to separate her from Isabel. Eventually she tells Isabel that she's sold Ruth, but actually she sent her to their other property in Charleston. When she learns of Isabel's espionage work for the patriots, she reveals the truth about Ruth's location to Isabel in order to blackmail her for good behavior. She tells her that Ruth will be drowned as punishment for her -- Isabel's -- misconduct.
Lady Seymour
She is the elderly aunt of Lockton. She lives on her own estate in New York City. When Isabel is sent to help her out, she takes a liking to the girl. Isabel physically saves her from the fire, and Lady Seymour promises to repay her with kindness. At the Lockton estate, Lady Seymour makes Isabel her personal servant, to help her with her recovery from the trauma of the fire. Lady Seymour then gives Isabel money, and tells her to run, as she dies.
