Mandie and the Dangerous Imposters

is the twenty-third book in the Mandie series.
==Book Description==
On a visit to her Cherokee kinpeople, Mandie discovers the troublemaking Tsa'ni has gone missing--and so has Mandie's uncle Wirt! Is this another of Tsa'ni's pranks, or could it have something to do with the strange men who have been spotted digging all over the mountain?
(Description from Mandie.com)