They first appear as a series of dots on astronomical plates, heading from Saturn directly toward Earth. Since the ringed planet carries no life, scientists deduce the mysterious ship to be a visitor from another star.The world's frantic efforts to signal the aliens go unanswered. The first contact is hostile: the invaders blast a Soviet space station, seize the survivors, and then destroy every dam and installation on Earth with a hail of asteriods. Now the conquerors are descending on the American heartland, demanding servile surrender - or death for all humans.

Members of an alien species called the Fithp have traveled to our solar system from Alpha Centauri in a large spacecraft, intent on taking over the Earth. The Fithp resemble man-sized, quadrupedal elephants with multiple trunks. They possess more advanced technology than humans, but have developed none of it themselves. In the distant past on their planet, another species was dominant, with the Fithp existing as animals, perhaps even as pets. This predecessor species badly damaged the environment, rendering themselves and many other species extinct, but left behind their knowledge inscribed on large stone cubes called Thuktunthp , plural of Thuktun in the Fithp language, from which the Fithp have gained their technology. The study of Thuktun is the only science the Fithp possess. The Fithp are armed with a technology that is superior rather than incomprehensible: laser cannon, projectile rifles, controlled meteorite strikes to bombard surface targets, lightcraft surface-to-orbit shuttles the size of warships.

Nominated for Hugo and Locus awards in 1986.