When a neighbor asks Nancy to accompany her to an old uninhabited mansion, she finds a witch tree symbol that leads her to Pennsylvania Dutch country in pursuit of a cunning and ruthless thief. The friendly welcome the girl sleuth and her friends receive from the Amish people soon changes to hostility when it is rumored that Nancy is a witch! Superstition helps her enemy in his attempt to get her off his trail, but Nancy persistently uncovers one clue after another to outwit her dangerous adversary.