With only a few days left of her summer vacation, Mandie goes for a short visit with Uncle Ned and his granddaughter, Sallie. But before leaving, Mandie receives a message that Tsa'ni, a Cherokee boy who is always stirring up trouble and playing tricks on others, wants to see her. Sallie says it's really important. When Mandie arrives, Tsa'ni is nowhere to be found, and she discovers that her Uncle Wirt has disappeared as well. Dimar, another Cherokee friend of Mandie's, tells her of strange diggings going on in the mountains nearby. Could the two mysteries be connected? What will Mandie do if someone else disappears? Mandie's hooked on another mystery. But is it dangerous?