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.

Everything Aoife thought she knew about the world was a lie. Her brother isn't at Ravenhouse. Her best friend isn't who she thought he was. And there's no such thing as the Necrovirus. Her mother didn't go mad from a dormant strain, she's simply allergic to iron. As is Aoife. Because Aoife is no ordinary girl. Like her brother, Conrad, she is half human and half Fae, from the land of Thorn. And now she's a fugitive, and beginning to realize that the destruction of the Lovecraft Engine was only the start of a cataclysm. Her world is falling apart when the dreams begin. Dreams of a mysterious figure telling her to go north, to the frozen wastelands of the Arctic Circle; and find the Brotherhood of Iron. The Brotherhood holds the secret that can put the world right again: a device known as the Nightmare Clock, which can be reached only in dreams. But can it actually fix what Aoife has destroyed? Or is someone using her to remake the world according to their own sinister visions? The only way for Aoife to find out is to embark on a journey that would surely be the end of any average girl - and to complete it before the land she calls home poisons her mind just as it did her mother's.

When Dean was shot and killed in the Arctic north, he was ripped not only from the Iron Lands but from Aoife Grayson's life. Aoife has sworn to bring her love back, even if she must face death to do it. But she can't get to the Deadlands on her own. And even if she can get there, her foe, Tremaine, will surely block her escape; it is his job to hold her in the Thorn Land, the fairie home of her mother, Nerissa. Aoife has never shied away from a fight. She'll do whatever she must to get out of the Thorn Land and to the Deadlands. But to rescue Dean, she must also face the other catastrophe that took place in the north. She must stop the apocalyptic chain of events she set in motion when she opened the Gate to the nightmare realm. Because if she doesn't, there will be no world to bring Dean back to.