In the city of Lovecraft, the Proctors rule and a great Engine turns below the streets, grinding any resistance to their order to dust. The necrovirus is blamed for Lovecraft's epidemic of madness, for the strange and eldritch creatures that roam the streets after dark, and for everything that the city leaders deem Heretical—born of the belief in magic and witchcraft. And for Aoife Grayson, her time is growing shorter by the day.

Aoife Grayson's family is unique, in the worst way—every one of them, including her mother and her elder brother Conrad, has gone mad on their 16th birthday. And now, a ward of the state, and one of the only female students at the School of Engines, she is trying to pretend that her fate can be different.