Its plot 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 in Allerton, Texas, young Amanda Post awakens in the middle of the night to her mother, Rita's, dying screams, as she is stabbed to death by an unseen assailant.

Thirteen years later, Amanda receives a phone call notifying her that her grandmother Harriet is on her deathbed.

There, she is met by Dr. Crawther, as well as Judge Stemple and museum owner Claude Kern, the latter of whom is hoping to acquire Amanda's grandmother's historical home after her death.

Later that evening, after Amanda receives several anonymous lewd phone calls, she has her doctor friend Nick come to examine her grandmother.

At his invitation, Amanda goes to visit Claude at the local historical society museum, where he shows her a mannequin he has styled to appear as her mother.

As Amanda loses consciousness, Stemple returns to the house, but is bludgeoned by Claude, hiding in the home's foyer.

When Amanda attempts to use the phone, she is met by Claude on the line, who continues to make threats and comment on her clothing.

[6] Executive producer Martin Jurow attended the film's premiere in Paris, Texas on May 3, 1974.