The Red Empress is the only home Erzelle has known since the day her family was lured aboard and murdered, victims of a grisly ritual meant to make the elite immortal. Erzelle plays her harp for the diners inside this ghoul-infested riverboat, knowing her own death looms, escaping through the music that's all she has left of her parents.

Her nightmare's upended in the space of a day by the arrival of Olyssa, a fellow musician, but so much more.

Erzelle is swept up in Olyssa's quest to find her ensorcelled sister Lilla, a journey across a mutated landscape that leads them to an enemy responsible for the deaths of millions. To stop the slaughter of countless more, the pair has no choice but to draw on the deadly magic that reshaped the world ... a power that's as dangerous to its wielders as it is to its foes, one that's killing Erzelle even as she fights to control it.