Chimal lives in an Aztec valley, where the serpent-headed goddess, Coatlicue, walks. When Chimal notices that all creatures entering the valley seem to come from the same place, he goes to investigate. Leaving the valley, he discovers that it is contained in a 'generation starship', which is run by a group who live lives similar to those of medieval monks.
Chimal first adjusts to life outside the valley, then sets about liberating the inhabitants of the ship.
This is regarded as one of Harrison's most literary novels.
"For the first fifty pages you'll swear that Harrison has been rummaging in an old trunk. Here is that tired old theme ... the lost community of Aztecs who have been cut off in a hidden valley by a landslide centuries ago. Presently they will discover the outside world - our world. The stalwart Aztec maverick may even fall in love with a beautiful white explorer... Of course, any reader of this magazine should know harry Harrison better than that. There are rumblings, even in the first chapters. The Aztecs are blond - that old Fair God bit again. Someone is feeding the vultures meat from an unspecified source. And surely we're not supposed to accept a snake-headed goddess? Trust Uncle Harry. On page 55, young Chimal follows the goddess through a secret door in the cliffs, with his whole tribe hunting him, and the story turns inside out. "
"Harry Harrison early proved his power as a novelist with Deathworld. More recently he has given us many examples of his versatility. The latest is Captive Universe ... This novel combines anthropological reconstruction with science fiction. A good part of it is a vivid and exciting picture of an Aztec civilization. There is interesting chapter-heading art by Harrison himself."
"This book is a crime. If it is as common a crime as smoking marijuana, it is no matter: the offense is the same. That it was committed by an author of Harry Harrison only compounds the crime. There was simply no reason for this book to have been written and no reason to read it ... There is nothing new in this, nothing exciting, nothing daring or original or imaginative, nothing but a contrived hackwork on a theme borrowed from writers who borrowed from writers who... That is not to say that the book is not well written. Each and every paragraph is technically perfect. Harrison has been writing too long not to know how to write a good, serviceable sentence. The first scene is the best piece of action writing to be found outside Laumer."
"In Captive Universe we appear to be getting more of the healthy outdoor life he celebrates in his Deathworld series. But something untoward is happening in an Aztec valley. Coatlicue, the goddess with the serpent heads, walks the fields. And why do all the vultures ascend with their prey to one particular spot on a high cliff? Chimal goes to investigate, and soon is in a very nasty situation ... To addicts of this genre, this nasty situation will not be entirely unfamiliar. However, Harrison brings his usual gusto to bear, and the result is a pleasing and exciting mystery, expertly resolved."
" ... a tricky piece of soc sci fi from the anthropology department ... it's written in the stiff journeyman prose that characterises too much of the science fiction I've encountered; an engaging drama of ideas without sufficient verbal solidity to make it a good novel."