Magic is starting to wane, it has been long gone in Tep's Town since Yangin-Atep went myth, and the traders of the caravans are finding it hard to ply their trade. Even worse, terror birds, enormous flightless birds with blades for wings, have started to attack the trade routes, almost completely halting trade.

Lord Sandry is tasked to find out where the terror birds are coming from and why, and to try and open the trade routes. For the trip he has the pleasure of Burning Tower's company, and her brother, the wagonmaster for the Feathersnake caravan. The terror birds are obviously being controlled, and that takes magic, so Tower's cousin Clever Squirrel is persuaded to come along as the caravan's shaman.

Sandry makes a name for himself by killing the terror birds and teaching others how to use non-magical means to stop the terror, as they track the birds back to Aztlan, where the enigmatic Emperor rules supreme. As they get closer it becomes clear that there is a god behind the movements of the terror birds, but which one and why?

I have in my collection almost every Niven and Pournelle collaboration, starting with "The Mote In God's Eye" (1974) and continuing through all of their "hard science" novels. This was the first fantasy novel penned by the pair that I've read, which is certainly an omission I felt needed to be addressed.

One aspect of Niven and Pournelle hard science novels is the inherent optimism. Even in the post-apocalyptic "Lucifer's Hammer", there is the promise of a brighter future due in no small part to technology. In "Burning Tower" I sensed a similar need to have optimism fuelled by technology. Sandry often thinks that his superior chariot and compound bow are weapons that need to be kept under wraps because they provide the Lords with an edge over what he perceives to be potential enemies.

The book leans heavily on Aztec history and even the terror birds, according to the afterword, appear to have basis in fact. I'm not sure this historical veracity is borne out with the mix of roman-style chariots and war methods, aztec human sacrifice, shamanistic magic and even unicorns that underpin the story.

The story has a lot of action in it, but for some reason it never really became the page turner it probably should have been. The anachronisms were probably a part of that and I had trouble suspending my disbelief long enough to truly enjoy the ride, and my experience, and love of the earlier hard science fiction of the team probably coloured my expectations.