The Spiral Staircase

Helen, a mute girl, attends a silent film screening in a Vermont inn. During the screening, a lame woman leaves for her room and is strangled by a killer hiding in her closet. This murder is noted as the third in a string of killings plaguing the community.

Dr. Parry drives Helen to the Warren estate, where she will work as a live-in companion for the bedridden Mrs. Warren. The sprawling mansion also houses a mix of relatives and staff with their own tensions.

Helen takes up residence as Mrs. Warren's live-in companion, moving into the large mansion alongside the other residents. Her presence unsettles a house full of hidden motives and potential threats.

In the mansion, the killer watches Helen as she pauses to look at herself in a mirror. The moment hints that Helen is being targeted and observed, especially given her vulnerability.

Mrs. Oates discusses the murder with Helen and expresses fear that the killer is targeting women with disabilities. The remark heightens the sense of a calculated pattern and imminent danger.

The ether bottle disappears, and Albert sends Mr. Oates into town to fetch a replacement. The theft adds a layer of logistics that the killer can exploit.

Mrs. Warren regains consciousness and urges Dr. Parry to take Helen to Boston to help her process the trauma of her parents' death and her muteness. Parry agrees to return later that evening to continue discussions.

Blanche asks to join Helen for the night and goes downstairs to fetch her suitcase. In the basement, the killer ambushes and strangulates Blanche, the most recent victim.

Helen discovers Blanche's corpse and is confronted by Steven. Fearing he is responsible, she locks him in the basement and flees back upstairs.

Helen attempts to wake Mrs. Oates, who has passed out, drunk on the professor's stolen brandy. She also struggles to reach Dr. Parry by telephone.

Albert finds Helen frantic and she writes on a notepad that Blanche has been murdered. He confesses to killing Blanche out of jealousy and explains how he arranged events to keep Helen isolated.

Albert expands on his theory of killing the 'weak and imperfect' and hints at his broader scheme. He mentions that he noticed Helen looked at herself in the mirror and appeared to have 'no mouth,' intensifying his fixation.

The constable appears at the front door and is kept occupied by Albert, who leaves a message that Dr. Parry cannot return that night. The delay deepens Helen's sense of being trapped.

Helen returns to the basement to free Steven but finds Albert waiting. Mrs. Warren arrives with a gun and shoots Albert, ending his murderous spree and exposing his role in the killings.

Mrs. Warren dies on the staircase in Steven's arms after revealing her suspicions about Albert. Helen, now able to speak, calls Dr. Parry to reunite with her and begin processing what happened.