The Borrower - Rebecca Makkai

Lucy Hull, a children's librarian in Hannibal, Missouri, finds herself both kidnapper and kidnapped when her favorite patron, ten-year-old Ian Drake, runs away from home. Ian needs Lucy's help to smuggle books past his overbearing mother, who has enrolled Ian in weekly antigay classes. Desperate to save him from the Drakes, Lucy allows herself to be hijacked by Ian when she finds him camped out in the library after hours, and the odd pair embarks on a crazy road trip. But is it just Ian who is running away? And should Lucy be trying to save a boy from his own parents?