The Unwritten Girl — James Bow

Rosemary Watson lives in the small town of Clarksbury, where news travels fast and gossip sticks around. Years before, her brother Theo suffered a nervous breakdown, and Rosemary, now entering junior high, is constantly teased about it. She wonders if she might go crazy like her brother, and she feels guilty for not being able to save him. She tries to hide in books, but even there she's uneasy: she can't stand to see characters suffer. She's happiest in the cool world of fact and figures.

Rosemary and Peter - the new kid in school with issues of his own - are thrown together, and soon find themselves on a life-or-death quest to rescue Rosemary's brother, who has lost himself in a book. With the help of Peter and her guide, faerie shape-shifter Puck, Rosemary must face the storybook perils of the Land of Fiction and learn to open her heart, before it is too late.