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"--