With her father Moses North, Mahala is deeply engaged in the underground railroad in upstate New York in the days before the Civil War. Her mind and heart are deeply bound to the cause; her bitter hatred for slavery, the loss of her twin brother some years before on one of their dangerous missions; her love for Dallas Ord, quiet Southerner who is also a zealot for the abolitionist movement - these are the bright strands of Mahala's life, a life of high purpose and danger.