Civil War veteran John Carter is chased by Indians to an Arizona cave. Mysterious fumes overwhelm him, and when he awakes he finds himself on Mars. He is soon captured by the warlike Green Men of Thark. He’s put under the care of a young female named Sola who is the only one of the creatures with a heart. There is soon another captive, a young girl from the Red Men, Dejah Thoris, a princess from Helium. Carter falls instantly in love with Dejah and helps her escape with Sola. There is a long sequence in the center of the book where Carter, accompanied by his “dog” Woola, is searching for Dejah while being captured and escaping from a series of Martian tribes. He finally ends up back with the Tharks, who are now captained by Tars Tarkas, Sola’s father. The join forces and attack the Red tribe of Zodanga, defeating them in time to save Dejay from having to marry the prince. Carter returns her to Helium, and they marry. Nine years later, the atmosphere plant shuts down when the caretaker dies. Only Carter has the way to open the doors. He struggles through the diminishing air and arrives just in time to open the doors and save Mars, but he passes out. When he wakes, he’s back in the Arizona cave.

Interesting, but really too busy to actually be good. I understand it was originally written as a pulp series with short chapters and regular cliffhangers, and that knowledge makes it more interesting, but it’s still pretty silly.