In this story, Cassie gets separated from her brother on a train and encounters Harriet Tubman, who leads her on the same path slaves used to escape on the Underground Railroad. Along the way, Tubman explains the history of slavery to Cassie, and to the reader, in a way that is factual, straightforward and appropriate for young children. The book provides a good overview of this period of American history and would be appropriate for parents to read with children who are just learning about slavery for the first time.