The Gods of Mars

After John Carter's arrival, a boat of Green Martians arrive on the River Iss and 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. Carter and Tars Tarkas discover that the Therns, rulers of Valley Dor, a white-skinned race of self-proclaimed gods, have for eons deceived the Barsoomians of the outer world by disseminating the myth that the pilgrimage to the Valley Dor is a journey to paradise. Most arrivals are killed by the beasts of Valley, the survivors enslaved by Therns.