A galloping horse interrupts a sleepy afternoon as Thaddeus rides into the life of young Harriet. The Fugitive Slave Act is about to send a river of freedom-seeking men, women and children to the historic Elgin Settlement in Canada, where the Underground Railroad has carried Harriet and hundreds more. She is determined to become a courier like Thaddeus for the secret black anti-slavery Order. As she welcomes newcomers to the Settlement, Harriet struggles with her feelings for Thaddeus while fighting for an equal place in the Order, and Thaddeus agonizes over the family he left behind in the North Carolina Great Dismal Swamp community.

Freedom Soldiers brings alive the turbulent and prophetic experiences of two young people freed from slavery who vow to destroy the hated system. Their story reveals the leadership and courage of self-liberated and enslaved black men and women who secretly worked to bring enslaved people to freedom and abolish slavery forever.