In the fourth book of this award-winning national park series, Tommy Bubba Jones and his sister, Jenny Hug-a-Bug, uncover amazing facts about the Grand Canyon while on a mission to solve a park mystery. This is no ordinary brother and sister duo, they are part of a legendary time travel family with a mission to preserve and protect our national parks and they have developed a reputation for solving mysteries in the parks. As they time travel back hundreds, thousands, and millions of years, they not only learn about the past, they experience it. They encounter all sorts wild creatures and plants. They meet the people involved in the establishment of this national park, they learn about the Native Americans that call this land home and they unravel some of the park’s secrets. Explore the Grand Canyon in a whole new way.