Here’s the Slashfilm plot synopsis: A Princess of Mars by Edward Rice Burroughs was first published in 1917. The movie will follow Civil War vet John Carter, who is transplanted to Mars, where he discovers a lush, wildly diverse planet whose main inhabitants are 12-foot tall green barbarians. Finding himself a prisoner of these creatures, he escapes, only to encounter Dejah Thoris, Princess of Helium, who is in desperate need of a savior.