The Warlord of Mars completes the story begun in A Princess of Mars and continued in The Gods of Mars, finally bringing together John Carter and his beloved Dejah Thoris, Princess of Helium. Carter last saw his beloved in the Temple of the Sun of the Holy Therns, with the blade of Phaidor descending toward her heart. But the exiled leader of the Therns has rescued his daughter and now wants revenge on Carter for exposing his evil cult.
In the shadows of the forest that flanks the crimson plain by the side of the Lost Sea of Korus in the Valley Dor, beneath the hurtling moons of Mars, speeding their meteoric way close above the bosom of the dying planet, I crept stealthily along the trail of a shadowy form that hugged the darker places with a persistency that proclaimed the sinister nature of its errand. For six long Martian months I had haunted the vicinity of the hateful Temple of the Sun, within whose slow–revolving shaft, far beneath the surface of Mars, my princess lay entombed—but whether alive or dead I knew not. Had Phaidor's slim blade found that beloved heart? Time only would reveal the truth. Six hundred and eighty–seven Martian days must come and go before the cell's door would again come opposite the tunnel's end where last I had seen my ever–beautiful Dejah Thoris.