On his first sea voyage away from the magical city of Cassaforte, seventeen-year-old Nic Dattore awakens to find the vessel overrun by marauding pirates—and everyone else on board kidnapped or killed. After slaying the pirate who attacked him, Nic tosses a torch into a cache of gunpowder and blows up the ship. Washed up on a deserted island, Nic and a motley crew of castaways decide to commandeer the pirate ship to get home. They battle pirates, assassins, and a cursed ship with a powerful secret while racing against time to save Cassaforte from a diabolical coup.