Eleven-year-old Tilly Pages, who has found comfort in her grandparents' bookshop since her mother's disappearance, now learns that she can bookwander into any stories, and decides to seek her mother.

Mr. Hardbattle, aided by his friends Miss Quint and resourceful thirteen-year-old Arthur, seeks a new place for all of the magic that has gone out of control and taken over his bookshop and home.

After several burglary attempts occur at the bookstore where he is working for the summer, Joe and Wishbone decide to investigate and discover that some of the most important clues to the mystery are in the books themselves.