Samantha Sherwood (Samantha Eggar) is on stage practicing a role while the stage director, Jonathan Stryker (John Vernon), watches by the spotlight. Stryker later drives Samantha to a mental institution to have her committed. After Dr. Pendleton (Calvin Butler) mentions Samantha's placid composure, she attacks Stryker with a letter opener. Attendants run inside the doctors office and take her away in a straitjacket. Stryker asks for a moment alone with Samantha and the two of them appear very happy. It seems that Samantha is a method actress and Stryker had suggested to her that the only way to play the insane title character of Audra is the stay in an insane asylum so Samantha can get a first hand look at what it is to be a mental person.
Samantha resides in the institution for some time as the weeks draw by, which soon turn into months, as she's surrounded by eerie and unstable residents. Stryker occasionally visits Samantha and is pleased to see her deteriorated state as her stay there is slowly dehumanizing her and thus will make her right for the role. But one day, Samantha reads the latest issue of Variety magazine to see that the casting for the movie Audra has begun. Angered that Stryker has abandoned her, she escapes from the asylum that night, breaks into his office, and throws photos of potential stars into the fireplace. Samantha stays for a few nights with an old girlfriend of hers who hides her until Samantha goes off saying "what I have to do won't take long."
Amanda (Deborah Burgess), one of the audition hopefuls, has a sexual role-playing game with her boyfriend and talks about the casting sessions. Later, Amanda is driving in the rain when she sees her freaky doll in the middle of the road. She gets out to look at it, and it seems to grab her. Someone gets in Amanda's parked car and drives towards her. Fortunately, it is only a dream as Amanda wakes up in her own bed with her boyfriend by her side. As Amanda gets up out of bed to look at her sleeping boyfriend, a person wearing a eerie and ugly mask grabs her by the hair and stabs her to death with a chef's knife, and then takes her doll sitting by the bed.
The next day, a group of very different actresses hoping to play the part of Audra arrive at Stryker's snow-covered dwelling. They are Patti (Lynne Griffin), a comedienne-aspiring actress always telling jokes and who moonlights at a local comedy clubs telling stand-up jokes. Brooke (Linda Thorson) is a veteran actress hoping the role will make her sagging stage and film career. Tara (Sandra Warren) is a tall, attractive actress hoping to make it big. Lauraine (Anne Ditchburn) is a timid and hesitant dancer with a skill in ballet. Christie (Lesleh Donaldson) is an ice-staking figure queen hoping the roll will start her acting career. Stryker arrives with the actresses sitting around the table until he notices that one of them is missing. The odd workman, Matthew (Michael Wincott), sits down with the women, in which Stryker mentions that Amanda is the actress whom is missing. Suddenly, Samantha arrives and sits at the table with the five other actresses which makes Stryker look very uncomfortable.
Later that evening, Tara is out in the so-called "casting Jacuzzi" with Matthew making the moves onto him. In the house, Stryker and Samantha are arguing about Stryker's decision to have someone else play Audra. Christie walks by, listens by the door and walks in where Stryker tells her that he and Samantha were rehearing a play that he wrote. He leads Christie out and to her room where he tries to make the moves onto her. Outside the house, someone picks up a sickle just as Stryker leaves Christie alone in her bed to weep over being forced upon.
The next morning, Christie goes out to the nearby frozen lake to skate. The music from her boom box suddenly stops. Christie skates over to the boom box and she finds the freaky doll buried under the snow. The masked killer is there on the ice and skates towards Christie with the sickle in hand. The killer swings and Christie is hit in her shoulder, but the skater fights back and knocks the killer down to the ice with the doll. Christie runs into the woods, but when she stops to rest beside a tree, the killer grabs her from behind and kills her.
Later that morning, Stryker is in a room with Patti, Tara, Lauriane, and Brooke when Samantha arrives saying that she wants to act and not be left out. Stryker has her sit in front of the others and he puts the same killer's mask onto her. He tells Samantha to seduce him without using words. "Make me love you", Stryker tells Samantha, who does not do anything. Stryker pulls off the mask and points to a mirror and tells Samantha that her face is a mask too.
Afterwards, Stryker talks to Patti who tells him a couple of jokes. He tells her that he does not think a casting session is necessary for her. Patti yells at him, claiming that she is as good as the other actresses. Stryker almost smiles and says that he is "enjoying a little bit of Audra".
Matthew is seen riding away on a snowmobile cart towards the woods to look for Christie. The unseen killer follows him.
Later that evening, Stryker asks Samantha where the hag mask is, to which Samantha does not know. Brooke, reading the script in her room, hears a noise and goes into the bathroom, where she discovers Christie's severed head in the toilet. She runs into a room where Stryker is working with Tara and Laurian. The director follows Brooke back to her room, but the severed head is gone. He calms Brooke down and the two of them kiss.
Meanwhile, Lauraine is practicing her ballet dancing in a studio room when the killer walks in...
A little later that night, Samantha sees Stryker in bed with a sleeping Brooke by his side. When Styker and Brooke are talking about Brooke being cast in the role of Audra, someone walks into the room and fires a gun at them in which both of them fly out the window. Hearing the gunshots, Tara walks outside where she sees the dead bodies of Stryker and Brooke and screams. She runs around the house looking for the others. She finds Laurian's dead body in her room, but she does not notice a dead Matthew floating in the Jacuzzi outside having been stabbed. Tara encounters the masked killer and is chased around the house. The chase leads to the props warehouse next to the house where Tara looks for a place to hide. Tara eventually bests the masked killer twice; first by luring the killer to stab at her coat enabling her to counter-attack, and then beats the killer with a wooden club, but each time the killer gets back up and resumes the pursuit. After hiding in an air vent, Tara crawls out when she thinks the killer has walked out of the room. But she makes a noise in which the killer runs back in and kills her by slashing her to death with the sickle.
A little later, Samantha walks into the kitchen where Patti is opening up a bottle of champagne. Samantha tells her about the institution and how Stryker committed and abandoned her so he can look for younger talent for the role of Audra which includes Patti and the younger actresses. Samantha tells Patti that she just killed Stryker for his betrayal as well as Brooke who happened to be there as his latest female conquest. Patti tells Samantha that she is celebrating that she will get the role, but becomes a little hurt and upset over the news of Samantha killing Stryker. Samantha tells Patti to forget about the role and just to back to where she came from and assures Patti that she will not harm her or any of her friends. Suddenly, Patti smirks at Samantha and says: "there's only me left". Patti tells Samantha that SHE killed all the other actresses to prevent them from claiming the role that she was meant to get. Patti grabs a butcher knife off the kitchen counter and stabs Samantha who screams.
The final shot shows Patti now doing her comedy bit in the same insane asylum where Samantha was committed before a group of residents most of whom are not paying attention to the deranged actress whom is apparently still pleased that she is still working in the entertainment business as the character of Audra.