Marc has been assigned to Jamestown, the US-Commonwealth base on Venus, near the great Venusian city of Kartahown. Set in a countryside swarming with sabertooths and dinosaurs, Jamestown is home to a small band of American and allied scientist-adventurers. But there are flies in this ointment - and not only the Venusian dragonflies, with their yard-wide wings. The biologists studying Venus' life are puzzled by the way it not only resembles that on Earth, but is virtually identical to it. The EastBloc has its own base at Cosmograd, in the highlands to the south, and relations are frosty. And attractive young geologist Cynthia Whitlock seems impervious to Marc's Cajun charm. Meanwhile, at the western end of the continent, Teesa of the Cloud Mountain People leads her tribe in a conflict with the Neanderthal-like beastmen who have seized her folk's sacred caves. Then an EastBloc shuttle crashes nearby, and the beastmen acquire new knowledge… and AK47's. Jamestown sends its long-range blimp to rescue the downed EastBloc cosmonauts, little suspecting that the answer to the jungle planet's mysteries may lie there, among tribal conflicts and traces of a power that made Earth's vaunted science seem as primitive as the tribesfolk's blowguns. As if that weren't enough, there's an enemy agent on board the airship…

In the “universe next door” first introduced in S. M. Stirling’s The Sky People, aliens terraformed Mars (and Venus) two hundred million years ago, seeding them with life-forms from Earth. Humans didn’t suspect this until the twentieth century. Then American and Soviet probes landed on our sister worlds and found life—intelligent life, at that. By the year 2000, all the great powers of Earth are contending for influence and power amid the newly-discovered inhabitants of our sister planets. In A.D. 2000, Jeremy Wainman is an archaeologist who has achieved a lifelong dream; to travel to Mars and explore the dead cities of the Deep Beyond, searching for the secrets of the Kings Beneath the Mountain and the fallen empire they ruled. Teyud za-Zhalt is the Martian mercenary the Terrans hire as guide and captain of the landship Intrepid Traveler. But she conceals a secret—one that links her to the enigmatic Ancients, the Lords of Creation who reshaped the Solar System in the time of the dinosaurs. When Jeremy and Teyud meet, the foundations of reality will be shaken—from the lost city of Rema-Dza to the courts of the Crimson Kings.