Following a long raiding expedition, the pirate airship Dawnhawk returns home. But repairs and relaxation will have to wait, as Captain Fengel, Lina Stone, and the rest of the crew find themselves caught up in an attack upon Haventown itself. Their enemy? An entire naval fleet mobilized by the Kingdom of Perinault, eager to crush the pirates as the first step in a glorious new age of conquest and imperialism.

The only hope for Haventown is an ancient Voornish superweapon, hidden away years ago by Euron Blackheart, the Pirate King himself. But the Perinese have secrets of their own, and Blackheart's motivations may not be what everyone expects.