| Term | Definition |
| Newport, R.I. | Isabel and Ruth are sold in a tavern in Newport to the Locktons. |
| New York City, 1776 | Setting for most of novel |
| Tea Water Pump | Water pump where Isabel goes to fetch fresh water for the Locktons. Uses her water errand as an excuse for other activities. |
| Isabel | Protagonist, 13 year old slave. Strong minded, willful, and very protective of her younger sister Ruth. Spies on Locktons for the Patriot commander. |
| Ruth | 5 yr old sister of Isabel. Prone to seizures. Serves Madam Lockton |
| Jenny | Tavern keeper who tries to save Isabel and Ruth by purchasing them in Newport instead of the Locktons |
| Miss Mary Finch | Isabel and Ruth's dead owner at the start of the novel. Miss Mary's will specified that Isabel and Ruth should be freed upon her death |
| Mr. Robert Finch | Miss Mary's nephew. Sells Isabel and Ruth to the Locktons despite Miss Mary's will. |
| Madam Lockton | Loyalist socialite in New York City. Often beaten by her husband. Mistreats Isabel and Ruth |
| Mr. Lockton | Loyalist involved in several schemes to help the British including providing bribery money and assisting in a plot to assassinate George Washington. |
| Becky | Paid, white servant in Lockton residence. |
| Lady Seymour | Mr. Lockton's aunt. |
| Curzon | Bellingham's slave boy. Wears signature red hat. Encourages Isabel to spy on the Locktons. First name is James |
| Colonel Regan | Patriot commander who Isabel supplies with information about Lockton and the Loyalists plans. Does not protect Isabel from Madam Lockton after she runs away. |
| Mister Bellingham | Curzon's master, Patriot cargo inspector |