But suddenly, out of the night sky, a common enemy appears – the Windborn, who come without warning to raid, burn, and kill. Hoping to turn the tide, Shae — the Bone Pirate’s first mate — enacts a daring plan to fight her way aboard a Windborn vessel.

The raid yields a prize — the airship’s captain who is, to Shae’s shock, a man. Together with a reluctant heroine, Bela, they learn the truth of their shared history: the Windborn and Seaborn come from the same people, split apart by blood magick when a race of immortal mechanical men betrayed their human makers. Now, these unlikely allies must make a desperate journey to confront the secrets of the past – and stop the dark magick at its source.