John Carter, a Civil War veteran, who in 1868 was trying to live a normal life, is "asked" by the Army to join, but he refuses so he is locked up. He escapes, and is pursued. Eventually they run into some Indians, and there's a gunfight. Carter seeks refuge in a cave. While there, he encounters someone who is holding some kind of medallion. When Carter touches it, he finds himself in a place where he can leap incredible heights, among other things. He later encounters beings he has never seen before. He meets a woman who helps him to discover that he is on Mars, and he learns there's some kind of unrest going on..
Andrew Stanton (screenplay by), Mark Andrews (screenplay by), Michael Chabon (screenplay by), Edgar Rice Burroughs (based on the story "A Princess of Mars" by)