The Warlord of Mars John Carter of Mars, Book Three

John Carter discovers that a First Born knows the secret of the Temple of the Sun and he and the Holy Hekkador Matai Shang want to rescue the Holy Thern's daughter, who is imprisoned with Dejah Thoris and another Barsoomian princess, Thuvia of Ptarth. John Carter follows them in the hope to liberate his beloved wife. His antagonists flee to the north, taking the three women along. Thereafter John Carter follows them untiring into the north polar regions where he discovers more fantastic creatures and ancient, mysterious Martian races. These he overcomes in battle, and is later proclaimed "Warlord of Barsoom" by his allies. This book is the last to feature Tars Tarkas, John Carter's ally, in any major role; indeed, the green Barsoomians of whom Tars Tarkas is an oligarch disappear altogether from most of the later novels.