The Ghost of Blackwood Hall — Carolyn Keene

When Mrs. Putney seeks Nancy Drew's help in recovering her stolen jewelry, the search for the thieves takes the teen-age detective and her friends Bess and George to the colorful French Quarter in New Orleans. But the quest is hampered by the strange behavior of Mrs. Putney and two young women who are being victimized by so-called spirits. How can Nancy fight these unseen perpetrators of a cruel hoax? And how can she help the gullible victims when the spirits warn them not to have anything to do with Nancy?

The young sleuth's investigations lead her to a deserted old mansion haunted by a phantom organist. How Nancy uses her own ghostlike tactics to outwit the ghost of Blackwood Hall and aids the police in capturing a group of sinister racketeers will keep the reader tense with suspense.