Nancy Drew (Janet Julian) has been kidnapped after working on a case involving a man named McCall (Colby Chester) who she had put in jail. After being missing for over six months the police close the case, so Carson Drew (William Shallert) calls on the Hardy Boys to help find Nancy. With no help from the police, the Hardys look through Nancy's old case to find some clues to her disappearance. Meanwhile Nancy has been held captive by a wealthy business man named Rathbone who was involved in larceny and fraud with McCall. It turns out that Rathbone hasn't left his penthouse in twenty-two years, since his wife Greta left him. Rathbone has gone crazy and believes Nancy is his wife, so he dresses Nancy in his wifes old lace dress and makes her watch old movies of his wife. Frank and Joe find themselves at Rathbones building from the clues that were in Nancy's notebook. A mysterious woman (Cathy Rigby) is starting fires within the building. While Frank is saving Nancy from Rathbone and the fire, Joe is trying to get everyone out of the building before it is completely consumed by the fire. In the end Nancy is saved, Rathbone is arrested and the mysterious girl admits to the arson. It turns out that the mystery girl is really Greta's daughter who was seeking revenge on Rathbone for destroying her mothers life which cased her to go insane and slowly die within a mental institute.