The Gods of Mars

After John Carter's arrival, a boat of Green Martians on the River Iss are ambushed by the previously unknown Plant Men. The lone survivor is his friend Tars Tarkas, the Jeddak of Thark, who has taken the pilgrimage to the Valley Dor to find Carter. Having saved their own lives, Carter and Tars Tarkas discover that the Therns, a white-skinned race of self-proclaimed gods, have for eons deceived other Barsoomians by spreading the belief that the pilgrimage to the Valley Dor is a journey to paradise. Most arrivals are killed by the beasts of the Valley, and the survivors enslaved or eaten by the Therns.