A Princess of Mars by Edgar Rice Burroughs

A Princess of Mars’, a science fantasy by Edgar Rice Burroughs, is story of John Carter, a confederate veteran of American Civil War, who after the war mysteriously gets transferred to Mars. On Mars, he falls in love with the princess of Helium, Dejah Thoris, and fights her enemies. He also restores the planet’s functionality and then succumbs to asphyxiation, only to awaken back on Earth, left to wonder what has become of Barsoom and his beloved.