Carla Moran (Barbara Hershey), a single mother with three children, is attacked by an invisible assailant. The first time it happens she's convinced she's raped by a man but when they check the house all the windows and doors are locked. When it begins to happen again she flees with her family to a friends. She confides that the man was invisible and her friend thinks she's crazy. During one of the attacks her sixteen year old son tries to intervene and gets his wrist broken by the invisible creature.
Carla goes to see a by-the-book psychiatrist, Phil Sneiderman (Ron Silver), who believes that she's really causing herself injury. He doesn't believe in anything supernatural. She goes along with him because she's afraid that it may be in her mind. But when she overhears two college parapsychologist talking about recording ghost activity she tells them about her experiences. They stay at her house for a night and witness it first hand. They believe her--and she's relieved because this means she isn't crazy after all. In fact, the head of the parapsychology department wants to try to capture this "entity" in frozen helium. They recreate the inside of her house within the University's gymnasium, where she'll stay until it appears. Then she'll retreat to a safe area and then release the gas, freezing the thing instantly. But, of course, things don't go as planned and it takes control of the freezing contraption and tries to kill her. The psychiatrist is the one who actually saves her before the whole thing explodes.
I enjoyed this movie far more now than I did when I first saw it in '82. It's a lot like POLTERGEIST, in a way, particularly with the psychic investigators (2 men and a woman). The special effects of the invisible Entity grabbing her, putting handprints on her bare flesh, all done with latex appliances and bladder effects, are convincing. Recommended.
Based on the book by Frank DeFelitta, who also wrote the screenplay.