Behemoth

Fresh from the Leviathan's escape, Deryn Sharp -- a commoner masquerading as a boy in the British Air Service -- and Alek, the exiled heir to the Austro-Hungarian throne, find their fragile truce tested when a German ship's Tesla cannon nearly destroys their airship mid-retreat. As the Leviathan makes for Istanbul, Alek plots to slip away and rejoin the war on his own terms, dragging a reluctant Deryn into his plans. Drawn into the political tangle of the crumbling Ottoman Empire, both find themselves caught between clashing factions in a war getting bigger by the day. The second novel in Scott Westerfeld's Leviathan trilogy.