First of a projected series, from the author of the fantasy Oath of Empire series (The Storm of Heaven, 2001, etc.). In Harlan's hypercomplicated far future—we seem to be in an alternate universe where the Mexica, assisted by Nisei Japanese, became dominant on Anahuac (Earth) and eventually established a galactic empire—it is the time of the Sixth Sun, 4-Flint. Impoverished Company archaeologist Gretchen Anderssen is ordered by the Imperial Navy to planet Ephesus III, a lifeless desert with an unbreathably thin atmosphere; a Company ship has fallen mysteriously silent and its scientific team is cut off on the planet's surface. Explorer Russovsky, it emerges, discovered an artifact and sent it up to the ship. A careless investigator breached the object, releasing an agent that consumed all organic material aboard the ship—crew and all. Gretchen soon finds another of the enormously valuable objects: they're a million years old and derive from the First Sun people. Also aboard the Navy ship, however, is an imperial judge, Green Hummingbird. He fears the First Sun people and their technology and refuses to let Gretchen keep the artifact. The science team is evacuated to the ship, but Russovsky turns out to be no longer human: she's a mineral copy. Hummingbird descends to the planet himself, intent on removing all human traces. Gretchen, vastly curious and determined not to let Hummingbird steal her artifact, follows him down to the surface.
An eerie, utterly compelling puzzler, replete with fascinating ideas and absorbing characters.