The fourth book of the Barsoom series, Thuvia, Maid of Mars takes up the story of Thuvia, now Princess of Ptarth, and Carthoris, son of John Carter and Dejah Thoris. Thuvia is betrothed to Kulan Tith, Jeddak of Kaol in an arranged marriage. She spurns the advances of a suitor, Astok of Dusar, who then plots to abduct Thuvia, and frame Carthoris for the crime, igniting a war between Kaol, Ptarth and Helium.