In a twilight land, two warring powers -- the Reds and the Blacks -- play out an ancient game of murder and betrayal. Then a Visitor from beyond the sky arrives to play a part in this dark and bloody pageant. From the moment he is found by two women who tend to the dead in the wake of battles, it is clear that the great game is to change at last.

It is the day after tomorrow, and society has been altered dramatically by experimentation that enables scientists to combine the genetic material of different species, mixing DNA of humans with animals. Loren Casaubon is an ethologist drawn into the political and social vortex that results with Leo -- a creature both man and lion -- at its center.

A young man named Rush That Speaks is growing up in a far distant world -- one that only dimly remembers our own age, the wondrous age of the Angels, when men could fly. Now it is the "engine summer of the world," and Rush goes in search of the Saints who can teach him to speak truthfully, and be immortal in the stories he tells. The immortality that awaits him, though, is one he could not have imagined.