Summer is almost gone, and third-grader Abby Spencer and her friends, the Book Bunch, are spending their time working on a play for the local public library, and visiting Abigail Flynn at the Evergreen Nursing Home.

Between working on the medieval project for third grade and helping move books and redecorate the children's section at the public library, Abby Spencer and her friends, the Book Bunch, have their hands full--but Mrs. Mackenzie has promised them a really special lunch as a reward.

Puzzled over what to write for a creative writing contest, Abby finds inspiration when her dog digs up an old key on a gold chain and she sets out, with the help of Mrs. Mackenzie the public librarian, to solve the mystery of the golden key.