Designed to both entertain and teach valuable lessons from United States history, this book follows two young detectives as they solve mysteries from the nation's past. Ninth in a popular series, this book features more maps, photos, and puzzles to be examined as Meg and Peter race across the country--from Plymouth, Massachusetts to San Francisco, California--to figure out the historical mysteries. Children are encouraged to participate in solving the mystery by answering questions, figuring out codes, and searching pictures for clues while learning important lessons about history, geography, and diversity.