Adelina is content to be a humble librarian with no magic, organizing ordinary books and leaving the magical section of the library to the management of the mysterious creature called a cervara . . . until she finds a misshelved spellbook that refuses to stay in its proper place. Despite warnings from the College of Magic and her superiors, she decides to return the book to the magical section, where she befriends the mysterious creature. Contrary to what she's been told, the cervara is trying to protect humanity from dangerous magic by hoarding it in the library. But is it also hiding an even greater danger?

Leon is a mage in his final year at the college who needs to write something impressive for his final thesis. But when he meets the charming Adelina, and she confides her discovery to him, Leon's world turns upside down. He's forced to try to mediate between the mysterious creature and the power-hungry magi who surround him, all while trying to pursue his favorite librarian.

Can Adelina and Leon protect the cervara from the world—and the world from the dangers of the library? Or will both sides be destroyed by the secrets they hide and the greed that drives them to seek forbidden knowledge?