The second book of an excellent series of adventure novels set in the South American back country. McKay, Knowlton and Ryan travel up the Tiger River in search of Inca treasure. Along with the Peruvian bandit Jose Martinez, they free a tribe of Indians enslaved by the Almagros to work in their gold mine. Martinez and the Indian survivors set out to unite other groups of The White People and establish a kingdom in a disputed area of the Andes between Peru and Ecuador. The American adventurers return to civilization with a vast quantity of gold.