After their parents' seedy old motel burns down on the same night they are visited by a strange man covered in skeleton tattoos, Cyrus, Antigone, and their brother Daniel are introduced to an ancient secret society and discover that they have an important role in keeping it alive.
For two years, Cyrus and Antigone Smith have run a sagging roadside motel with their older brother, Daniel. Nothing ever seems to happen. Then a strange old man with bone tattoos arrives, demanding a specific room.

Less than 24 hours later, the old man is dead. The motel has burned, and Daniel is missing. And Cyrus and Antigone are kneeling in a crowded hall, swearing an oath to an order of explorers who have long served as caretakers of the world's secrets, keepers of powerful relics from lost civilizations, and jailers to unkillable criminals who have terrorized the world for millennia.

N. D. Wilson, author of Leepike Ridge and 100 Cupboards, returns with an imagination-capturing adventure that inventively combines the contemporary and the legendary.