The House on Haunted Hill

Jeff is asked to investigate whether Merston Manor, a house which is impossible to sell, is really haunted after two previous psychics were scared off. He is looking into a jewel theft and sends Marty to the manor instead. Marty initially believes the ghostly sounds to be genuine but they are actually being made by the jewel thieves who are using the house as their den and want to scare off visitors. The gang capture Jeff and Jenny, Jeannie's sister but Marty comes to their rescue by appearing to one of the psychics previously frightened off, who summons help.