John Carter of Helium has rescued Thuvia, princess of Ptarth, from the Therns and now Carthoris, John Carter's son, has fallen in love with her. But Thuvia is stolen away by Astok, Prince of Dusar, Ptarth's rival. Carthoris tracks Thuvia across Barsoom and rescues her only to find she is already betrothed to Kulan Tith, Jeddak of Kaol, an ally of Helium.

"Thuvia, Maid of Mars" was first published as "Carthoris" in All-Story Weekly (April 8, 15, 22, 1916). The first hardcover edition was published by A.C. McClurg & Co., October 30, 1920. The original edition was bound in an olive green cloth with black lettering on the spine and front. The dust jacket, in color was by P.J. Monahan. A frontispiece, and nine illustrations were done by J. Allen St. John.