The premise is that - in a universe once identical to our own - the Spanish who discovered the Americas brought back with them a plague to which the Aztecs were immune. Europe, decimated in the sixteenth and seventeenth centuries, was not able to fully exploit the new continent, leaving the Aztecs to learn from the Spanish and thus evolve into a superpower. By the end of the twentieth century, the Aztec Empire, already in control of China and most of North and South America, are ready to invade Europe.
The narrator and hero comes in the unlikely form of Princess Catherine, sister to Victoria, and to Richard, the nice-but-dim heir to the throne of the United Kingdom. It's exciting and fast-paced from the outset, and is certainly a fascinating and enjoyable read, if it is at some points let down by the Aztecs' rather unlikely level of scientific development which seems both fantastic and rather too incredible a feat to have achieved by 1993.
However, the book is very subtle in its examination of the warring cultures and political systems and despite the exciting and chilling denouement one finds oneself seeing the resistance - of which Princess Catherine feels she is a part even if working mostly alone - as behaving just as badly, if not worse, than the occupying forces.
On the other hand, as we are seeing this world through Catherine's eyes, one could argue that we. along with Catherine, are being seduced by Aztec propaganda and misinformation.
An intriguing character is Bevan, who is employed as Catherine's 'sidekick' throughout. A Welsh militant and an anti-Royalist, he neveretheless appears to be working with Princess Catherine against the Aztecs. His true role is never fully revealed and it is left to the reader to decide for themselves for which side Bevan was batting.
The novel works extremely well simply because of this ambivalence, not only with Bevan, but with other characters such as Extepan, heir to the Aztec Empire who may, throughout the novel, have been working with the best of motives, but from a different cultural perspective.
There is also Mia, Extepan's 'handmaiden' whose enigmatic presence arouses the suspicions of both Catherine and Extepan's first wife. The most important question Evans raises is whether a United Earth under the Aztecs would be altogether a bad thing. The world would be culturally unified for the first time which would lower the probability of war between nations.
Compared to our own world of international squabbles and terrorism, being part of the seemingly altruistic Aztec Empire seems reasonably attractive.
Ultimately and quite ingeniously, Evans once more leaves it to the reader to decide who, if anyone, did the right thing.