When a rich city kid disappears from nearby Camp Whispering Pines, the three cousins find themselves in the middle of a serious mystery. A ransom note raises the stakes, and the police start tracking down a kidnapper. But Jeff, David, and Claire learn that the boy was last seen headed toward fabled Skull Cliff, possibly in search of its sparkly treasure. The clues just don't add up. As they put all of their evidence together, the cousins start to believe that there never was a kidnapping. But that doesn't mean the boy is out of trouble. He's in more danger than ever