Inspired by the author's Welsh ancestors, who immigrated to Philadelphia and the North Carolina frontier in the 1750's, the novel follows the stirring adventures of sisters Ardath and Gwyn. After their mother disappears in Wales and their estranged father dies in the smallpox epidemic on their voyage across the stormy Atlantic, they assert their growing maturity in Ben Franklin's colonial Philadelphia. However, in hopes of finding their mother, they leave the safety of civilization, bound for North Carolina along the primitive wilderness track that would become the Great Wagon Road -- where the wilds of frontier America sorely test their resourcefulness and resolve.