A satirical fable, a political allegory and an ecological warning from the author of The Three-Body Problem. In a sunlit clearing in central Gondwana, on an otherwise ordinary day in the late Cretaceous, the seeds of Earth's first and greatest civilization were sown in the grisly aftermath of a Tyrannosaurus' lunch. Throughout the universe, intelligence is a rare and fragile commodity - a fleeting glimmer in the long night of cosmic history. That Earth should harbour not just one but two intelligent species at the same time, defies the odds. That these species, so unalike - and yet so complementary - should forge an alliance that kindled a civilization defies logic. But time is endless and everything comes to pass eventually... The alliance between ants and dinosaurs, was of course, based on dentistry. Yet from such humble beginnings came writing, mathematics, computers, fusion, antimatter and even space travel - a veritable Age of Wonder! But such magnificent industry comes at a price - a price paid first by Earth's biosphere, and then by all those dependent on it. And yet the Dinosaurs refused to heed the Ants' warning of impending ecological collapse, leaving the Ant Federation facing a single dilemma: destroy the dinosaurs, destroy a civilization... or perish alongside them?