The Campground Kids receive an envelope containing secret information about a lost artifact called a "Navigem." The kids quickly piece together that this is more than just a favor; it is a mission from their Uncle Elliot. Finding the legendary Navigem will be no small task, as it has been missing for decades. Rumor has it that an outlaw hid it in South America; however, Uncle Elliot's clues seem to point toward Arches National Park. The kids must get up to speed with their secretive uncle and find the Navigem before others catch on.