"Before Jake’s grandfather died, he was on the trail of a centuries-old mystery. And he has entrusted that mystery to Jake, leaving behind a set of hidden codes, riddles, maps, and other clues that lead Jake and his friends on a scavenger hunt into the most wild and rugged wilderness of the national parks....The scavenger hunt takes Jake and his friends, where few people venture to go, into the depths of the Grand Canyon. Jake, Amber, and Wes encounter new dangers and find their friendship tested as they follow the clues Jake’s grandfather hid away in the old scrapbook. The stakes are higher, and the history goes deeper as the three kids put their heads together to solve a puzzle that is perhaps hundreds of years in the making." --Goodreads.com