The Hidden Staircase is a young-adult mystery novel first published in 1930 and written under the collective pseudonym Carolyn Keene. The story follows 18-year-old amateur detective Nancy Drew as she investigates a series of seemingly supernatural events at the historic Twin Elms mansion, home to two elderly women who believe the property is haunted. At the same time, her father, lawyer Carson Drew, becomes the target of a threatening criminal scheme tied to a disputed claim over railroad land. Carson represents one of the affected parties, making him a danger to those who want the case buried. Through these two interlocking plots, the novel explores themes such as Rational Logic Versus Superstitious Fear, The Power of Female Autonomy, and The Way Greed Corrupts Social Trust.

The Hidden Staircase is the second book in the Nancy Drew Mystery Stories series. The version of the novel most widely read today is a 1959 revision overseen by Harriet Stratemeyer Adams, who took over the Stratemeyer Syndicate after her father Edward Stratemeyer’s death. Adams initiated a project to revise the first 34 books in the series, modernizing the language and plot and removing racial stereotypes present in the original 1930 edition. The Nancy Drew series had sold over 80 million copies worldwide by the late 20th century and has been adapted multiple times for film and television. The Hidden Staircase was adapted into a 1939 film starring Bonita Granville and a 2019 film titled Nancy Drew and the Hidden Staircase.

This guide refers to the 1987 Grosset & Dunlap edition.

Content Warning: The source material and guide feature depictions of death, physical abuse, and emotional abuse.

Plot Summary

Eighteen-year-old amateur detective Nancy Drew receives a call for help from her friend Helen Corning. Helen’s great-aunt Rosemary Hayes and great-grandmother Miss Flora Turnbull believe that their historic mansion, Twin Elms, is being haunted.

A man named Nathan Gomber visits Nancy’s home with a warning. He claims that Nancy’s father, lawyer Carson Drew, is in danger because of his work for a railroad building a new bridge. Gomber represents Willie Wharton and other landowners who feel that they were cheated, and he advises Nancy to stay by her father’s side. Nancy is torn, but after Helen and Aunt Rosemary arrive and describe the eerie music, moving shadows, and stolen jewelry at Twin Elms, her desire to take the case grows.

Nancy discusses the case with her father, who dismisses Gomber’s threats. He explains that Gomber is hiding Wharton to invalidate a land-sale contract and extort more money from the railroad. Carson reveals that he has a lead on Wharton’s location in Chicago, Illinois, and encourages Nancy to investigate the haunted house. The threat soon feels more real when a large truck at the bridge construction site rolls toward Nancy and her father, forcing them to dive into the Muskoka River to survive. Nancy discovers footprints made by men’s business shoes, confirming that the incident was a deliberate attack.

Nancy travels with Helen to the Twin Elms estate in Cliffwood, where they learn that Miss Flora’s valuable pearl necklace has just vanished from her room despite all doors and windows being locked. Nancy’s initial investigation reveals no signs of a break-in. That same evening, Miss Flora’s radio plays without being turned on, and Gomber appears, revealing that he’s trying to buy the mansion at a low price by exploiting the haunting rumors.

Shortly after Aunt Rosemary sends Gomber away, the parlor’s crystal chandelier begins to sway violently. Nancy deduces that someone was in the room above and rocked the floor. During her test to prove this, Helen screams, having seen a terrifying face at the window. Nancy finds no intruder and theorizes that a mask was used. The hauntings continue, with an owl appearing in Miss Flora’s locked room at midnight and a long-haired, unshaven face materializing in the parlor only to vanish, causing Miss Flora to collapse from shock. A police guard, Tom Patrick, patrols the grounds but sees nothing, leading Nancy to suspect a secret entrance.

Nancy’s confidence in her father’s safety collapses when she receives a telegram, supposedly from him, canceling his planned return. The Drews’ housekeeper, Hannah Gruen, then calls to reveal that the telegram is a hoax; Carson had confirmed that he was coming home. Nancy decides to investigate what happened to him.

At the Cliffwood train station, a frightened taxi driver named Harry, encouraged by a kind nurse named Miss Skade, finally admits what happened. He drove Carson from the station, but two other men boarded the cab, feigned a medical emergency, and handed him over to a waiting car after threatening Harry’s family. Harry describes one abductor as having a “crinkly” ear.

Nancy’s search at Twin Elms leads her to a cave near the estate, where she finds a recent River Heights newspaper with a classified ad for a used-car dealer torn out. While leaving the cave, she spots a man with the same wrinkled ear examining her car; he flees before she can intercept him. The police identify him as Samuel Greenman, a man with a criminal record. Back at Twin Elms, the danger sharpens when the hall ceiling collapses, nearly crushing Nancy and Helen.

Nancy and Helen discover a secret passageway hidden behind a large cabinet in the parlor, which contains a listening post allowing anyone inside to overhear conversations in the kitchen. Nancy concludes that the “ghost” has been monitoring their plans. Meanwhile, the railroad lawyers inform her that they will concede to the landowners’ demands by Monday if her father doesn’t return.

Convinced that Gomber is behind the kidnapping, Nancy asks the police to shadow him, only to watch him leave Twin Elms moments later. They pursue him but lose him in the town of Hancock. Upon returning, they learn that Gomber threatened Nancy and the others to coerce the frail Miss Flora into signing over the mansion. Shortly afterward, Nancy glimpses a light in the window of the vacant neighboring estate, Riverview Manor, but the realtor informs her that it was just sold to Gomber.

The police capture Greenman, and Nancy persuades both Harry the taxi driver to identify him and Greenman himself to confess his minor role in the abduction. Greenman describes the man who drove Carson away but refuses to name his partner. The realtor for Riverview Manor, Mr. Dodd, decides to give Nancy the key so that she can look around. Inside the dusty mansion, Nancy and Helen find a hidden panel in a closet; Nancy tumbles down a secret stone staircase into a subterranean tunnel connecting the two estates, and Helen follows. Deep in the passage, a man orders them to stop: It’s Willie Wharton, who matches the description of the man who drove the car away with Carson.

Wharton confesses that Gomber hired him to play the ghost and frighten Miss Flora, using a notebook he had found that detailed the hidden staircases. He admits to taking the drugged Carson from the taxi but insists that Gomber immediately took custody and that he doesn’t know where Carson is now. Convinced of his sincerity, Nancy brings Wharton into Twin Elms, where he validates his signature on the land contract before a notary, foiling Gomber’s scheme. Acting on a hunch, Nancy leads the police into the secret passageway, where they find a padlocked iron door. Behind it, in a hidden dungeon, they find Carson alive but weakened by repeated drugging.

As the group brings Carson out, another officer reports that Gomber and his remaining accomplice were captured outside Riverview Manor, with all stolen items recovered. Gomber confesses his plan to build a housing project on both properties. With her father safe and both mysteries resolved, Nancy celebrates her victory.