A Burning in the Bones (Waxways, #3)

"After taking control of House Brood, Ren and Theo dreamed of using their newfound influence to change the rest of Kathor, but now they find their efforts being countered by the other great houses, who have no interest in a world where they enjoy less power. No one understands that better than the Tin'Vori siblings. The return of their ancestral home was a decade in the making, but they're eager to keep rising from the ashes. Nevelyn begins researching House Brood--and ends up face-to-face with an enemy that's already slouching toward the gates of the city. The one enemy no one can avoid: a plague. The victims experience strange bruising, an unquenchable thirst, and a temporary disruption in magic. When doctors trace the illness to its source, they find another mystery: corpses placed in strategic locations around the city. As Ren leads the hunt for the culprits, she'll find herself two steps behind a devious enemy whose sights are set on an unexpected prize: the city's magic"--Amazon.