Freedom's Price by Michael MacColl
Eliza Scott isn't quite a slave, but she's not free either. She's not a prisoner, but her family lives in a jail. Eliza, who attends a secret floating school on the Mississippi River because it's illegal for her to read, says she understands how dangerous her situation is--but her parents know she's not afraid enough. When a devastating cholera epidemic strikes the city, Eliza discovers she will have to be clever and resourceful to escape a slave catcher and the worst fire in St. Louis' history.