 The fifty years of American westward expansion between the 1830s and 1880s are viewed through the experiences of the Prescott and Rawlings families, as they migrate by the Erie Canal, continue over the prairies from St. Louis during the California gold rush, suffer through the Civil War, and finally help build the railroads on the plains and bring law and justice to the frontier. Along the way they meet mountain men, journey by wagon train, deal with Native Americans, and face outlaws in the southwest.