The Gods of Mars (Electronic Paperback on CDROM)

First Published - 1912-1913.
In 1886 John Carter figured out how to send himself back to Barsoom (Mars). Once back he learns that Dejah Thoris and Tars Tarkas have undertaken the final pilgrimage down Iss. He is himself trapped in the valley of Dor, where hideous green plant creatures and white apes attack and eat all the pilgrims who succeed in finishing the arduous journey. Carter learns that the Therns have been preying upon the pilgrims, and in turn the First Born have been preying on the Therns. After discovering (and meeting) his son Carthoris in the pits of the First Born, John Carter overthrows their corrupt religion and Issus is killed by her own people as the forces of Helium and the Green Hordes devastate the Therns and First Born. Dejah Thoris and Thuvia, a princess befriended by John Carter, are trapped in an underground dungeon with Phaidor, daughter of Matai Shang, for one year.