The Grimm Legacy by Shulman, Polly

Elizabeth has just started working as a page at the New York Circulating Material Repository - a lending library of objects, contemporary and historical, common and obscure. And secret, too - for in the repository's basement lies the Grimm Collection, a room of magical items straight from the Grimm Brother's fairy tales. But the magic mirrors and seven-league boots and other items are starting to disappear. And before she knows it, she and her fellow pages - handsome Marc, perfect Anjali, and brooding Aaron - are suddenly caught up in an exciting, and dangerous, magical adventure.