Jeannie Fogel and her brother Robert have been sent to spend the summer in the small town of Lost Creek in the Sierras. Both are sure they'll be bored, but when Jeannie stumbles across clues leading to a lost treasure and Robert becomes convinced he has spotted Bigfoot, their vacation takes on new excitement. Investigating the past of the town, its environs and its geography, they find clues to locate the lost treasure, turning a bored days in a great adventure.