Hannah's world is shaken when she discovers her family's involvement with the Underground Railroad. When runaways find their way to her Virginia home, she must decide if she will play it safe or join her family to help the slaves escape. In Philadelphia, her friend Sarah is drawn into the life of a seven-year-old orphaned slave, whose health and mental state has been shattered by the evils of slavery. As the danger increases, the girls must find the courage they need to act before it is too late.

Two Quaker girls, Hannah Brown, granddaughter of the most active abolitionist in slave-holding nothern Virginia, and Sarah Smith, daughter of "conductors" on the Underground Railroad in the free state of Pennsylvania, correspond before the start of the Civil War.