Who is the protagonist of the novel Chains?

Chains, written by Laurie Halse Anderson, focuses on the story of thirteen-year-old Isabel. Isabel used to be a slave to a lady who had promised her freedom, but she is sold to a cruel and violent family who live in Manhattan. The book is set during the 18th century, around the time of the American Revolution. The family Isabel now works for are Loyalists—people who want the colonies to stay under the rule of the British monarchy. Another slave, Curzon, tells Isabel that she can spy on the family she now works for and pass along information to the Patriot rebels. Curzon tells her that if she spies on the family, she can go free and leave New York. Isabel is in a difficult situation for a long time, and her beloved sister is even sent away. Isabel learns to stand up for herself and her sister, and in the end she and Curzon escape to freedom.