Helium, a spoiled princess and John Carter's daughter, rejects Gahan, Jed of Gathol, as a suitor and foolishly flies off into a great storm. Gahan gives chase. By the time he finally catches up to Tara, she has forgotten who he is, and he assumes the name Turjun, a panthan mercenary. Together they challenge the power of O-Tar, Jeddak of Manator, whose barbaric nation of Red Men have preyed upon Gathol for centuries. The Manatorians have elevated Jetan, Martian chess, to an unprecedented level of skill and excitement: they use live chessmen who fight for live princesses. Gahan finds himself fighting for Tara on the chessboard of Manator, and haunting O-Tar's palace.