Hannah is a 14-year-old girl who recently lost her parents and survived smallpox. Left with a facial pockmark and limited options, she soon finds herself bound into a seven-year indentured servitude contract at the grand Province House in Boston. She possesses a deep love for horses and a unique talent for mimicking voices, using her keen observational skills to survive in an unfamiliar, politically charged environment.

As the royal governor of Massachusetts and commander-in-chief of British-ruled America, General Gage enforces the Crown's laws upon an increasingly restless colonial population. He resides in the Province House with his family and a large staff. He attempts to balance his duty to the British government with a desire to maintain peace among the local residents.

Mrs. Gage is the American-born wife of the British military governor, placing her in a precarious social and political position. She runs the massive Province House household while managing the delicate sensibilities of her guests and staff. Her divided loyalties cause her visible distress as tensions rise in Boston.

Will is a newcomer to Salem whose family recently purchased Promise from Hannah's aunt. He sympathizes with the colonial Whigs and takes a keen interest in the political disputes brewing in Boston. He respects Hannah's bond with her horse and quickly establishes a strong connection with her.

Meg is a 15-year-old girl living as a ward of the Gage family while her British officer father serves in England. Privileged and accustomed to getting her way, she resents the restrictions placed upon her movements due to the brewing colonial unrest. She requires constant attention and frequently requests carriage rides to escape the confines of the mansion.

Caleb works as the stable boy at the Province House, managing the general's horses and sleeping in the stable quarters. He holds quiet sympathies for the colonial cause and actively despises the British soldiers who occupy Boston. He knows the hidden layout of the property and introduces Hannah to the city's covert political gatherings.

Catherine serves as the cook for General Gage's household. She provides a warm, steadying presence for the younger servants and takes Hannah under her wing upon her arrival. She observes the growing political tensions with a cautious eye while maintaining order in the kitchen.

Lydia is the stern overseer of the Gage household staff. She enforces discipline with cruel efficiency and harbors a deep disdain for colonial customs. She constantly watches the lower servants for infractions and readily hands out severe reprimands.

Paul Revere is a prominent silversmith and a central figure in the Sons of Liberty. He organizes political resistance against British policies and gathers intelligence regarding troop movements. He serves as a leader for the younger colonists who wish to resist the Crown's authority.

Dr. Church is a respected physician and a prominent member of the Sons of Liberty. He holds a strong reputation within the patriot community and frequently attends meetings to discuss colonial grievances against the British parliament.

Phoebe is Hannah's aunt and legal guardian following the death of Hannah's parents. She considers her niece a financial burden and swiftly liquidates the family's assets. A staunch Loyalist, she shows little warmth toward Hannah and orchestrates the girl's indentured servitude for a quick profit.

Promise is a black gelding originally gifted to Hannah by her late father. The horse possesses remarkable instincts and maintains an unbreakable bond with his former owner. He represents Hannah's final connection to her family and her past life in Salem.

Gabriel is a pale gold Spanish stallion gifted to General Gage. The horse suffers from severe anxiety and reacts violently to the harsh disciplinary methods employed by the British soldiers. He requires patience and gentleness to calm down.

Lieutenant Pratt is a young, arrogant British military officer stationed in Boston. He rides a distinctive rust-colored horse named Red Roy and displays open contempt for the colonial population. He uses his position to court favorable attention from young women of status.

Phillis is an acclaimed poet who was formerly enslaved. She moves within elite Boston circles, observing the rising political tensions with a quiet, careful demeanor. She corresponds regularly with high-ranking individuals in the city.

Sarah is a vocal, red-haired neighbor in Salem with strong Whig sympathies. She acts as a supportive presence in Hannah's life, offering small kindnesses and observing the shifting political dynamics in their small town.

Joseph is a quiet man living in Boston who takes a romantic interest in Catherine. He works as a publisher, producing materials that comment on the escalating conflict between the colonies and British authorities.

Dr. Warren is a physician and an influential member of the Sons of Liberty. He provides medical care to the colonial community while simultaneously organizing political resistance against British laws.

Mrs. Dudley serves as the housekeeper at the Province House. She runs the domestic side of the grand mansion with a gentle but firm hand, ensuring the staff completes their duties while offering a much kinder presence than the strict overseer.