It starts with simple atmospheric opening credits. Helen McCord (Dorothy McGuire) is on the long winding staircase of the mansion where she is employed as a servant. At one point she hears the wind howling outside and covers her ears. This is ironic since she’s mute and unable to make sounds of her own. Later when she’s targeted by a serial killer, she will struggle to cry out for help.
The first murder takes place in town. Siodmak presents a group of locals watching a silent movie. The camera tilts up to the ceiling and we see a woman about to change her clothes in the room above the theater. A man is hiding in the closet. We just glimpse his eye. Then there is a shot of her outstretched arms putting on a piece of clothing, being caught off guard by the killer.
A physician named Dr. Parry (Kent Smith) shows up, but there’s nothing he can do for the woman who’s been pronounced dead. He notices Helen and offers to take her home. They travel by horse and buggy to the remote country estate where she lives and works for an invalid woman named Mrs. Warren (Ethel Barrymore). Also staying at the mansion with Mrs. Warren are her stepson Albert (George Brent) and her son Steven (Gordon Oliver). One of these men is the killer. Not Dr. Parry.
As Dr. Parry and Helen ride towards the estate, it is clear he is smitten with her. In their relationship he does all the talking, but not all the communicating since she is still able to express her feelings. He drops her a short distance from Mrs. Warren’s home. As she approaches the front gate, a storm comes up. What makes this so interesting is how Siodmak skillfully weaves the more idyllic aspects of life in 1906 Vermont with danger that seems to exist in hidden places. Close-ups linger on Helen’s delicate features, and her mannerisms indicate a fragile quality.
The other characters at the house are depicted in contrast to Helen. Besides Mrs. Warren there’s Mrs. Oates the clumsy housekeeper (Elsa Lanchester); and a strict nurse (Sara Allgood) that Mrs. Warren drives to distraction. We are also shown a young secretary named Blanche (Rhonda Fleming) who is romantically involved with Mrs. Warren’s son Steven. When Blanche becomes the killer’s next victim, Helen believes Steven might be responsible. She enlists Albert’s help, not realizing he is the actual culprit.
There are effective camera set-ups inside the mansion. Especially when Siodmak and cinematographer Nicholas Musuraca zoom in on Albert’s eye watching Helen. Then they show Helen who symbolically has the mouth area of her face blurred. Over the soundtrack is heard the sound of thunder outside. These are very stylized images of activity in the house, mostly from the point of view of a homicidal voyeur, as only Siodmak could create and film them.
The last sequence is the most spectacular part of the movie. Helen realizes Albert is the killer, and she tries to get away from him. Upstairs Mrs. Warren has realized what extreme danger they are all in now. She has been bedridden for most of the story. But she is able to summon her strength and carefully lifts herself out of bed. Then she gets a gun.
Mrs. Warren reaches the top of the stairs as Helen is ascending in an attempt to get away from Albert. Mrs. Warren observes what is happening. She is very sick and about to die, but she manages to successfully aim and fire the gun. Albert has been shot in the chest and spirals all the way down to the bottom of the staircase. Steven suddenly shows up and Mrs. Warren dies in his arms. Meanwhile Helen has screamed in horror, suddenly reclaiming her voice. She makes her way to the phone to call Dr. Parry. Never before has anyone been so happy to hear from her.
THE SPIRAL STAIRCASE airs occasionally on TCM.