In this captivating urban fantasy debut, a librarian charged with protecting a secret magical archive must team up with a very peculiar man to find her missing twin brother.

Every person has a life book that holds their fate. Why doesn't he?

Deep beneath the Edinburgh Central Library lives the Arcane Archives: a secret collection of magical books containing the life stories, past and future, of every person alive or dead. Archivist Astra Knight has the rare ability to read these books. Her job is to keep them—the destinies within their pages—safe, and their existence hidden from non-magical folk. When her twin brother, Orion, goes missing, Astra vows to do whatever it takes to find him, including accessing his life book unsanctioned . . .

Doing so is risky and very illegal, but Astra will stop at nothing to save her brother. Her search leads her to the mysterious, charming and non-magical Castor Yates, who seems to be connected to Orion but has no memory of him—and who, most impossibly, has no life book of his own . . .

When Astra realizes that Castor is inexplicably being hunted by dangerous magical creatures, she strikes a deal with him: She'll help protect him if he helps her find Orion. Together, along with a banshee, a bartender and a demon cat, they set off to the Isle of Skye, the place they believe Orion vanished from. But as Astra and Castor grow closer, and the questions about Orion's whereabouts grow more sinister and complex,  Astra must figure out who she can really trust, and quickly—before time runs out for her and her twin.