Edgar Rice Burroughs 
The Gods of Mars 

This of course is the story of John Carter's return to Mars in search of "the incomparable" Dejah Thoris and hopefully save her again from "a fate worse than death." John Carter who is the "greatest swordsman on two planets" lands in the wrong place. He ends up in Mars Heaven, so to speak, which is far from that he soon learns. And the adventure begins.