In an alternate 1914 Europe, fifteen-year-old Austrian Prince Alek, on the run from the Clanker powers who are attempting to take over the globe using mechanical machinery, forms an uneasy alliance with Deryn, who, disguised as a boy to join the British Air Service, is learning to fly genetically engineered beasts.

In an alternate 1914 Europe, fifteen-year-old Austrian Prince Alek, on the run from the Clanker Powers who are attempting to take over the globe using mechanical machinery, forms an uneasy alliance with Deryn who, disguised as a boy to join the British Air Service, is learning to fly genetically-engineered beasts.

Scott Westerfeld presents the sequel to his hit steampunk novel, Leviathan. In the midst of conflict with the Clankers, the Darwinists' war efforts rely on the behemoth, the largest, most feared creature in the British navy. Deryn, posing as a boy so that she may serve in the Air Service, finds herself aboard the Leviathan along with Alek, the heir to the empire, who is also in disguise. However, when the Leviathan's mission goes awry, Alek and Deryn must team up and outrun the relentless enemy.

Continues the story of Austrian Prince Alek who, in an alternate 1914 Europe, eludes the Germans by traveling in the Leviathan to Constantinople, where he faces a whole new kind of genetically-engineered warship.

Illustrations and text provide detailed looks at the machines, uniforms, creatures, and characters of the Leviathan book series.