It is a special honour when Max and Marty Mitchell are invited as guests to the annual gathering in the village of Tumbling Waters. As the boys are about to discover, however, it is not all fun and games. In a friendly athletic contest Max and Marty slip from a rope bridge when the rope snaps. But was it an accident? Max and Marty-with the help of their friend Sammy Red Fox-are on the trail of another mystery!