Stirling's charming second pastiche of 1930s planetary romances (after 2006's The Sky People) moves from Venus to Mars, where different Terran factions vie to pick up the pieces of the Tollamune emperor's shattered realm. Archeologist Jeremy Wainman, sent by the U.S. Aerospace Force to explore the lost city of Rema-Dza, promptly falls in love with Martian mercenary Teyud za-Zhalt; no surprise that she turns out to be heir to the long-vanished Crimson Dynasty, or that they rush off to thwart an attempt to usurp the Ruby Throne. Soon they find themselves fighting a pack of feral airship engines and questing after the invisible crown of the first emperor. Stirling successfully creates a truly alien environment (Rugs crawled to envelop the feet), and his flair for the dramatic and obvious affection for the Mars of Burroughs, Brackett and Bradbury almost make up for his inclusion of pirates with eye patches, heavily armored guards riding fat-tired, self-propelled unicycles and other moments of near-parody.