Canadian horror movie “Black Christmas” (1974) starring Olivia Hussey, John Saxon, Margot Kidder among others.
A slasher is on the loose, and he is targeting young females in a sorority house. The girls get obscene calls from some unknown person. Claire Harrison (Lynne Griffin) is the first one to get killed. Her father was supposed to meet her the next day at 1.30 p.m. but when she does not arrive, he becomes alarmed and goes to the sorority house to inquire.
Other killings follow one after another, meanwhile the local police get involved, they post a lookout outside their house. Jess (Olivia Hussey) is the one who reports the obscene calls to the police station and she has a boyfriend Peter who is a wannabe concert pianist but with a terrible temper and attitude problem. He gets rejected in an audition and goes on to break the piano.
Barb (Margot Kidder) is the more bolder type, she insults the obscene caller and dares him. She has a drinking problem plus asthma. There is a house keeper, who also has a drinking problem, she has stashed her liquor at various places in the house which is in a mess overall and needs cleaning.
It all ends in a climax scene, but the story obviously leaves enough room for a sequel plot to arrive. Horror movies thrive on sequels until people get bored with them. The killer’s face is never shown in the movie. IMDB 3/10