The wren in the Holly Library
(Book)

"Some things aren't supposed to exist outside of our imagination. Thirteen years ago, monsters emerged from the shadows and plunged Kierse's world into a cataclysmic war of near-total destruction. The New York City she knew so well collapsed practically overnight. In the wake of that carnage, the Monster Treaty was created. A truce...of sorts. But tonight, Kierse--a gifted and fearless thief--will break that treaty. She'll enter the Holly Library...not knowing it's the home of a monster. He's charming. Quietly alluring. Terrifying. But he knows talent when he sees it; it's just a matter of finding her price. Now she's locked into a dangerous bargain with a creature unlike any other. She'll sacrifice her freedom. She'll offer her skills. Together, they'll put their own futures at risk. But he's been playing a game across centuries--and once she joins in, there will be no escape" --,Dust jacket.