Mackinac Island is a summer vacation spot in Michigan where no cars are allowed, so everyone uses horses and bikes to get around. Thirteen-year-old Hunter Martineau lives on the island year around and knows everything about the place.Well, almost everything. When bikes start to mysteriously disappear all over the island, Hunter is determined to catch the thief and claim the reward money. But that isn't so easy, even for someone as smart as Hunter.Hunter...