Alek and Deryn are on the last leg of their round-the-world quest to end World War I, reclaim Alek’s throne as prince of Austria, and finally fall in love. The first two objectives are complicated by the fact that their ship, the Leviathan, continues to detour farther away from the heart of the war (and crown). And the love thing would be a lot easier if Alek knew Deryn was a girl. (She has to pose as a boy in order to serve in the British Air Service.) And if they weren’t technically enemies.

The tension thickens as the Leviathan steams toward New York City with a homicidal lunatic on board: secrets suddenly unravel, characters reappear, and nothing is at it seems in this thunderous conclusion to Scott Westerfeld’s brilliant trilogy.

It is the cusp of World War I, and all the European powers are arming up. The Austro-Hungarians and Germans have their Clankers, steam-driven iron machines loaded with guns and ammunition. The British Darwinists employ fabricated animals as their weaponry. Their Leviathan is a whale airship, and the most masterful beast in the British fleet.

Aleksandar Ferdinand, prince of the Austro-Hungarian Empire, is on the run. His own people have turned on him. His title is worthless. All he has is a battle-torn Stormwalker and a loyal crew of men.

Deryn Sharp is a commoner, a girl disguised as a boy in the British Air Service. She's a brilliant airman. But her secret is in constant danger of being discovered.

With the Great War brewing, Alek's and Deryn's paths cross in the most unexpected way...taking them both aboard the Leviathan on a fantastical, around-the-world adventure. One that will change both their lives forever.