Don’t Open the Door!, also known as Don’t Hang Up, is a 1974 American horror film, directed by S. F. Brownrigg and starring Susan Bracken, Larry O’Dwyer, and Gene Ross. Its follows a young woman who returns to her hometown to care for her ailing grandmother, where she is tormented by disturbing phone calls from a deranged maniac.
In 1962, Amanda Post wakes up to the sound of her mother’s dying screams. She finds her mother, Rita, dead in bed, having been stabbed by an unknown assailant. Amanda comes face to face with the killer, but he lets her go.
Thirteen years later, Amanda receives a call informing her that her grandmother Harriet is on her deathbed. She returns to Allerton, Texas, for the first time since her mother’s murder and arrives at her grandmother’s large home. There, she meets Dr. Crawther, Judge Stemple, and museum owner Claude Kern. Claude is hoping to acquire Amanda’s grandmother’s historical home after her death. Amanda wants to have her grandmother admitted to a hospital, but Dr. Crawther explains that it would go against her grandmother’s wishes. Later that day, in a private conversation with Claude, Stemple alludes to knowing that Claude murdered Amanda’s mother years ago. Later that night, Amanda receives several anonymous lewd phone calls. She calls her doctor friend Nick to examine her grandmother. Nick suspects that the medication Crawther administered her grandmother has kept her sedated. While Amanda is sleeping, she is awoken by the feeling of someone touching her, but Nick dismisses it as a bad dream.
Amanda visits Claude at the local historical society museum, where he shows her a mannequin he has styled to look like her mother. Amanda is angered and disturbed by this and storms out of the museum. It soon becomes clear to Amanda that Claude and Stemple are vying for her grandmother’s home. Stemple offers Amanda a lump sum for the house, which she angrily denies. Stemple is persistent, telling her he will return that night after she reconsiders. Meanwhile, Crawther is summoned to meet Stemple at the historical society. Upon arriving, he is bludgeoned to death by Claude, who is trying to eliminate anyone who might stand in his way of acquiring the house.
- Susan Bracken as Amanda Post
- Charles E. Campbell as The Stranger
- Peter Haskell as Mr. Post
- Angela Greene as Mrs. Post
The entire movie was filmed at a single location – the movie producer’s own house.
” S.F. Brownrigg is kind of a uncelebrated gem of the grindhouse era, establishing a lot of tropes that would later be used in much more popular movies. ” 
“If you were born later than me, you may find this movie slow moving and not as filled with terror as you hope, particularly with the sinister VHS cover image that I attached to this review. Not all movies need to have a killing every two minutes and have geysers of gore. This movie does so much more with less.” 
“S. F. Brownrigg’s Don’t Open the Door! is a potentially memorable (albeit not particularly gory) slasher (or maybe “proto-slasher”) film, so how come it’s not better remembered? Well, unlike Bob Clark’s Black Christmas, Don’t Open the Door! didn’t have quite the star power.”