So I’m writing an essay on Chains about differences and similarities between Isabel and madam lockton

"Madam" Anne Lockton is 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.

Isabel is almost a character foil to Madam Lockton. 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.