John Carter's son, Carthoris, falls in love with his father's true friend, Thuvia of Ptarth, but she has been promised to another and is kidnapped by a third! Carthoris, suspected of the crime, spends the entire novel in efforts to rescue her and restore her to her fiancé. The adventures introduce to us a philosophical system or fringe science that challenges our conception of the nature of reality itself. (Summary by Thomas Copeland)