In Kansas, Mary Henry (Candace Hilligoss) is riding in a car with two other young women (Sharon Scoville & Mary Ann Harris) when a man (Larry Sneegas) and his buddy challenge them to a road race. During the race, the women's car is nudged by the boy's and plunges off a bridge into a muddy river. Three hours after the police start dredging the water to look for them, Mary miraculously surfaces on the river bank, but cannot remember how she survived.

Mary moves to Salt Lake City, where she has been hired as a church organist. While driving through the desert, Mary's radio starts playing nothing but strange organ music, and she has visions of a ghoulish, pasty-faced figure simply called "The Man" (Herk Harvey). She also sees a large, abandoned pavilion on the shores of the Great Salt Lake. A gas station attendant (Dan Palmquist) tells her the pavilion was first a bathhouse, then a dance hall, and finally a carnival before it closed.

In town, Mary rents a room. She meets the proprietor (Frances Feist), who informs her that there is another lodger staying there. Mary unpacks her suitcase and goes to the church where she will be playing the organ. At the church she meets the minister (Art Ellison) and is invited to play the organ for the first time. At the minister's offer, Mary takes a ride out to the pavilion at the lake. She is stopped from entering by the minister who warns her that it is prohibited to enter.

When she returns to her lodgings Mary meets a creepy man, John (Sidney Berger), the only other lodger, who wants to become better acquainted. Mary however, retreats as she is not interested. That night, she becomes upset when she sees The Man downstairs and retreats to her room. John brings her coffee and a bottle of whiskey at breakfast time before she goes shopping. Mary begins experiencing terrifying interludes when she becomes invisible and inaudible to the rest of the world, as if she simply were not there. When The Man appears briefly in front of her in a park, she flees, into the nearby arms of a Dr. Samuels (Stan Levitt). He tries to help her in his nearby office, acknowledging he is not a psychiatrist.

Mary's new employer, the minister, is put off when she declines a reception to meet the congregation. When she practices for the first time, she finds herself shifting from a hymn to eerie music. In a trance, she sees The Man and other ghouls dancing at the pavilion. The minister, hearing the strange music, denounces it as sacrilege and insists upon her resignation.

Mary had agreed to meet John after church and they go to a bar. Terrified of being alone with her nightmares, Mary says she wants John's company. When they return home, he is invited to her bedroom door. John tries to convince Mary to let him stay the night, but she walks away, apparently uninterested. Nevertheless, he follows her to her bedroom, where she sees The Man in the mirror. Frightened, she tells John what has been happening to her. He leaves, believing she is losing her mind.

After going back to Samuels' office, Mary believes she has to go to the pavilion. However, Mary is confronted by The Man and his fellow ghouls. She tries frantically to escape, boarding a bus to leave town, only to find that all the passengers are ghouls.

It is just a nightmare; she awakes in her car. In the end, she is drawn back to the pavilion, where she finds her tormentors dancing, a pale version of herself paired with The Man. When she runs away, the ghouls chase her onto the beach. She collapses as they close in.

The following day, Samuels, the minister, and police go to the pavilion to look for Mary. They find her footprints in the sand and they end abruptly in a complex group of prints. Back in Kansas, the girls' car is pulled from the river. Mary's body is in the front seat alongside the other two women. She was dead all along.

A 1962 American independent horror film shot on a budget of $33,000 in Lawrence, Kansas, and Salt Lake City, produced and directed by Herk Harvey and written by John Clifford from a story by Clifford and Harvey, and starring Candace Hilligoss. Its plot follows Mary Henry, a young woman whose life is disturbed after a car accident. She relocates to a new city, where she finds herself unable to assimilate with the locals, and becomes drawn to the pavilion of an abandoned carnival.

The film has been contemporarily noted by critics and film scholars for its cinematography and foreboding atmosphere. The film has a large cult following and is occasionally screened at film and Halloween festivals, and has been cited as a wide-ranging influence on numerous filmmakers, including David Lynch, George A. Romero, and Lucrecia Martel.