"Adventures in Marble Mountains" tells the story of six eleven-year-olds and their favorite teacher on a thrilling end-of-summer backpacking expedition, embarking on a ten-mile hike into the wilderness. Among them are Diego and Debbie, resourceful twins equipped with survival and first aid skills acquired from their worldwide hiker grandfather and their grandmother, an ER trauma nurse. Their expertise becomes crucial when two fugitive brothers stumble upon their campsite, injuring their teacher, demanding supplies, and holding them captive. At the time of their arrival, Diego was luckily hidden from sight after climbing midway up a tree to secure and tie up the food bag out of the reach of bears. After waiting for hours, he seizes the first opportunity to slip away unnoticed and begins his ten-mile trek back to the ranger station to seek help. He knows he is their only hope. As the hours pass, the criminals discover that a kid is missing because of the extra pack and sleeping bag. One remains at the camp while the other sets off to find Diego. In a twist of fate, Diego finds an unexpected ally, while Debbie and their friends use their wit and inner strength to protect and care for their teacher and outsmart the malevolent intruder. Will Diego reach help in time?