John Carter has freed Mars from Issus the false goddess whose tyranny once ruled the entire planet but at a great personal cost Dejah Thoris his beloved princess was taken by Matai Shang a renegade priest determined to avenge the planet's shattered religion Activating a doomsday device to destroy the fragile Martian atmosphere Shang flees into the unknown regions of the north Carter aided by his son Carthoris & trusted alien pet Woola must unite the many races of Mars
- despite the ages of distrust & open warfare among them
- for the singular purpose of averting Judgment Day!