The adventures of Deryn (a girl masquerading as a boy in the British Air Service) and Alek (undercover heir to the Austro-Hungarian throne) continue in this alternative history of World War I which began with Leviathan (Simon Pulse, 2009). Intrigue and double-dealing drive the plot as the teens are swept up in a British ploy to keep the Ottomans from joining forces with the Germans. When Deryn runs into trouble on a top-secret mission from her commander she ends up in Istanbul, a hotspot of conflicting loyalties. Deryn hopes to be reunited with Alek, who escaped from the airship Leviathan . She even contemplates telling him the truth about her identity—he doesn’t know she’s a girl—as her feelings for him start to run deeper than friendship. But Alek’s alliance with resistance fighters in Istanbul raises unexpected complications, not the least of which is his friendship with a fierce and beautiful young woman named Lilit. As in Leviathan , steampunk elements and fascinating possibilities of Darwinism add to the setting of this novel, with ingenious genetically engineered creatures and mechanical wonders part of the richly imagined world. (Ages 10–14)