On a trip to a retired police captain's country home, the boys and their friends find him missing and themselves plagued with mysteriously threatening happenings that seem related to an old local legend.
While flying, Nancy sees a car go off the road, and reports it. The bridge is out to that section of road, however, and the police don't believe her. Searching for the car leads her to a young mechanic, and a stolen car ring.
While investigating the disappearance of a missing scientist, the boys begin to doubt their senses when they discover an isolated estate loaded with bizarre illusions.
Nancy's eccentric aunts are selling their property. The day before the deal is reality, a burglar steals all the documents. When Nancy goes to her aunts to explain, she hears mysterious voices in the walls.
To raise money for charity, Nancy revives a play in a theater that is supposed to be haunted. Actors from the original cast return to do the play, but they are all acting suspicious, and Nancy is determined to discover the secret of the theater phantom.
Frank thinks he sees a girl who went missing years ago. When he tries to talk to her she claims that she is someone else. Frank and Joe soon find that she's mixed up in something illegal.
During a charity carnival, the wealthy hosts have jewelry stolen from their safe. A young Hispanic friend of Nancy's is accused, after having been seen on the property. Nancy believes the case has more to it than it appears.
