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 gathers clues and follows suspects to secret places. But every lead turns out to be a dead end - until the thief gives himself away, and Hunter realizes that he is in real danger. Along the way, Hunter makes new friends, grows closer to his dad, and learns why his heritage as an Ottawa Indian is so important to him. Full of fun and surprises, Mystery on Mackinac Island is about adventure, loyalty, and the discoveries of growing up.