Subsequently, Carter is reunited with old pal (and Chief/Jeddak of Thark) Tars Tarkus and discovers that the "paradise" that the valley is reputed to be is really a deception; Dor is run by the Therns (who aren't as omniscient as they appeared in the recent John Carter film), who feed most arrivals to the plant men and keep any survivors left as slaves.
Carter, understandably, is outraged by the Therns' practices, but he's got more to worry about. Besides fighting his way back to his wife Dejah Thoris (who was expecting their first child when he got sent back to Earth), Carter, with new allies such as liberated slave girl Thuvia, pirate Xodar, and a mysterious Red Martian youth, has to battle such old and new enemies as phoney godesses, the Warhoons and the Zogandans, as well as the Therns, one of whom, the female Phaidor, has taken a "fatal attraction"-style liking to him. Everything culminates in a series of one exciting action sequence after another, leading to a nail-biting cliff hanger ending, where Dejah may be in deadly danger.
More confident in his story telling skills this time, Burroughs delivers a solid and thrilling adventure tale that keeps the reader glued to the page. The author also gets in some nice commentary on how religion can be misused to permit all kinds of horrible behavior. At one point, Carter is even tried by the Zogandans for telling the truth about the Valley of Dor (which in Barsoom is supposed to be the closest thing to the afterlife).