When Jason Gridley of Tarzana discovered what he termed the Gridley Wave, a hitherto unknown form of radio wave, his intentions were not only to contact the inner world of Pellucidar, but also the more remote world of Barsoom. Contact it he did and the first to respond to the call was none other than Ulysses Paxton, formerly of Earth and currently a Jed of Duhor. The author, taking temporary custodianship of the communication machine for Mr. Gridley, was told of the strange and compelling tale, by Mr. Paxton, concerning Tan Hadron, a simple fighting man of Mars, and the incredible story of adventure and love that nearly destroyed all of Barsoom....