"Chains" is the story of thirteen-year-old slave Isabel's journey to discover her inner strength and fight for her freedom amidst the depravity of slavery and the upheaval of the Revolutionary War that divided America.

The novel opens on the day of Miss Mary Finch's funeral. Miss Mary Finch was the owner of Isabel and her little sister, Ruth. Before Miss Finch died, she ensured that both girls would be given their freedom in her will, but an evil relative of Miss Finch sells the two girls back into slavery for a profit. The girls' new owners, the Locktons, are devout Loyalists living in New York. They are minorities in the divided city as most in the colonies support General Washington and his desire to free America from British rule. On her first day in New York, Isabel is confronted by a Patriot officer's slave, a boy named Curzon, who asks Isabel to spy on her new masters to help the Patriot cause. He knows that messages from the Loyalist army may pass through the Locktons' home, and he hopes Isabel will share that information with the Patriot Army. He promises that his master will ensure Isabel's freedom in exchange for her help. Although she is wary, Isabel agrees.

Isabel quickly realizes that the Locktons view her and all other slaves as not human beings. They talk about intensely private affairs in her presence because as a slave, she is invisible to them. It is easy for Isabel to gather condemning information but she knows that if she is caught consorting with a Patriot soldier, she will be beaten, sold, or worse, killed. It is only when Madam Lockton begins beating Ruth and eventually sells her to the highest bidder, that Isabel gets serious about her spying duties. She gathers the most useful information for the Patriot Army, a list of soldiers seeking to assassinate General Washington, and runs to the Patriot barracks. The Patriot general that promised to save Isabel turns his back on her once she shares what she knows, and Isabel is returned to the abusive hands of Madam Lockton. As punishment for her insolence, Madam Lockton brands Isabel's cheek with the letter "I." Isabel fears all hope is lost until she learns that the British, if they remain control of the colonies, will seek to free all slaves. If she is free, Isabel may be able to find her sister and reunite her family. She reaches out to the Loyalist leaders but is once again rebuked.

At the same time, Isabel's friend Curzon enlists in the army in the stead of his master, hoping that his bravery, should he live through the battle, will earn him his freedom. He is captured by the Loyalist Army and held as a prisoner of war in horrendous winter conditions. When Isabel hears of this, she begins visiting him, bringing him food and warm clothes. Knowing that she no one to depend on but herself, Isabel hatches an ingenious plan to escape enslavement. On the night of the queen's birthday ball, Isabel escapes from the Lockton home and with the help of a kindly prison guard, helps rescue Curzon from certain death. She steals a rowboat and rows through the night, ultimately ending up in the free state of New Jersey. After years of abuse and struggle, Isabel is free.