Addy: An American Girl
All of the historical American Girl books are excellent on audio (yep, even my boys enjoy them, and we all learn a whole lot while listening). Highly recommend!
FROM THE PUBLISHER
Meet Addy Walker, a courageous nine-year-old girl growing up during the Civil War. When her poppa and brother are sold to another plantation, Addy and her mother take the terrible risk of escaping to freedom in the North. To get away safely, they must leave Addy's baby sister behind in the slave quarters; her cries could cost them their freedom. As Addy and Momma slowly build a new life in Philadelphia and struggle to bring their family together again, Addy comes to realize a powerful truth: freedom has great costs.