Meg follows a series of notes hidden in her grandfather's house to solve an old mystery of a missing baseball signed by Babe Ruth. The reader is challenged to interpret each clue before Meg solves it. Ages 7 to 10 years. In the book that launched her adventures, Meg follows a series of notes hidden in her grandfather's house to solve an old mystery of a missing baseball signed by Babe Ruth. The reader is challenged to interpret each clue before Meg solves it.