Nancy Drew is checking up on a friend when she meets Rosemary Turnbull. The elderly woman has been living peacefully with her twin sister, Floretta, in the family mansion for thirty years—until recently. In the last few weeks, the Turnbull twins have noticed many peculiar things—strange noises and music at night, shadows all over the walls. . . . And items are vanishing. Rosemary isn't easily frightened, but she is getting annoyed. Floretta, on the other hand, thinks the house is haunted and wants to sell it. Rosemary would prefer to stay and heartily accepts when Nancy offers to look into their troubles. But when the young sleuth arrives at the old manor, Nancy wonders if it's really haunted or if something more sinister awaits her inside . . .
Originally published in 1930, The Hidden Staircase is Nancy's second adventure. It was adapted for the 1939 and 2019 films of the same name, Nancy Drew and the Hidden Staircase.
Carolyn Keene is an author pen name that was used by many different people—both men and women—over the years. The company that established the Nancy Drew series, the Stratemeyer Syndicate, hired a variety of ghostwriters to fulfill the role. This pseudonym assured anonymity for the creators.