A magazine article offering a large reward to anyone who can find a missing medieval stained-glass window intrigues Nancy. She asks Bess and George to join her on a search in Charlottesville, Virginia. Before the three friends leave River Heights, their adversary tries to get them to postpone the trip. But no luck. Nancy is determined to carry through her plans.

During the girls' investigation of old southern mansions, they encounter a ghost who turns the tables and makes them disappear. Eerie sounds come from a beautiful estate that is surrounded by a high brick wall. Why will the owner allow no one to enter?