The movie begins with Donna (Snow) coming home with her friend Lisa (Davis) and Lisa's mom from the movies. Once they pull up in front of Donna's house they say their goodbyes and Lisa and Donna have a short discussion about cheerleading tryouts, but Donna isn't going to try out this year (note: this is Donna's sophomore year).
Donna walks inside of her house and hangs up her jacket. The t.v. in the family room is on when Donna walks in the house and she calls out to tell her family that she is home, but she get's no response.
When she puts her jacket in the closet she thinks she hears a noise and turns around and there is nothing behind her.
She walks past the couch to go up stairs and then the camera turns to her dead father at the bottom of the couch where he had been murdered by a cut to the throat.
She walks upstairs and trips over her brother's baseball bat and makes a small shout. She takes the bat to her brother's room and when she opens the door she see's him laying on the bed and tells him that she slipped over the bat.
Then she tells him to turn the television volume down and pokes him in the side revealing the slit to his throat and the blood under his chest. She lets out another small scream and hears running from her parents bedroom and a man yelling "Where is she?", then Donna hides under the bed.
While she is under the bed, she see's her mother run in and the killer, Mr. Fenton (Scheach) right behind her. He pushes the mother down and asks her where is Donna. The mother says she doesn't know and then he hits her and she falls to the floor. He asks her one more time and then the mother turns her head to the direction of the bed where Donna is hiding under and then the killer stabs the mother five times in the stomach.
Donna witnesses her mother being killed and holds in her scream. Once she realizes that the killer has left the house she runs downstairs and tries to flag down a police car. Then Donna hears a voice in her ear that says "I did it for us". It was the killer. Donna turns around and screams when she see's him and then the screen blacks out.
Donna is now in her school psychiatrist room and she just finished telling her about the nightmares Donna has been getting about the night the killer killed her family.
"And then what happens" the psychiatrist asks, "and then I wake up, just like I used to" Donna says. And then the psychiatrist tells Donna that the killer is locked up and far away and can only hurt her in her dreams. And then the psychiatrist asks Donna what color is her prom dress.
Now Donna and her friends Lisa and Claire (Stroup) are in a beauty salon getting their hair done for prom and Donna is explaining her dress, then Clair and Lisa make a joke about Lisa's dress and her boyfriend Ronnie (Penny).
Donna's hair dresser gives Donna a mirror and tells Donna to look at her hair and in the background of Donna's reflection she thinks she see's the killer standing by a bus stop and then she gasps and looks behind her to see that there is no man.
About an hour or two later Donna is getting ready for her prom in her house and she walks into her bathroom to freshen up. She opens her medicine cabinet to put on some make up and she think's she hears a noise, then when she realize's it nothing she closes the cabinet and screams because she thought her aunt Karen's (Gilsig) reflection was the killer.
After they have calmed down Donna's aunt asks Donna if she has been taking her anxiety pills, and Donna replies no and tells her aunt that she wants to remember what happens tonight and not feel numb.
And then Donna's date and longtime boyfriend Bobby (Porter) rings the doorbell and Donna goes downstairs and gives hima hug and kiss and the give eachother their corsages that they got for eachother and take a picture.
Now Donna, Bobby, Lisa, Ronnie, Clair, and Claires date Michael (Blatz) are in their limo going to their prom and they are taking pictures and having a good time.
The next scene takes you to the police department where Detective Winn (Elba) is at his desk going over files when Detective Nash (Rinsone) comes in with a fax. Detective Nash gives the fax to Winn and Winn curses and then calls a number to confirm if the fax is true about the killer that has escaped from prison.
When Detective Winn gets off the phone Detective Nash asks what's going on. Detective Winn explains the story about one of Donna's teacher's that got obsessed with her and how her parents got freaked out and got the teacher fired and he still was in communication with Donna so the parents got a restraining order and the teacher flipped out and killed Donna's father and brother and how Donna had to watch her mother die. The he explains how Donna started getting notes from him a few weeks ago.
Now Donna and her friends have arrived at their prom which is at a fancy hotel and they see one of the school girls that hates them named Crissy (Davis). They compliment her work on the dance and she doesn't care what they say. While in the hotel they see their P.E. teacher and have small chit chat.
After they have been in the dance hall for a few minutes where the prom is being held Ronnie tells them that he is going to get the keys for their room.
When Ronnie reaches the desk there is a man giving his information so he can get a room. He tells the room keeper that his last name is Ramsley. And then Ronnie comes up and tells the room keeper that he needs three keys to room 312 which the room that they are all staying in for the night. The Mr."Ramsly" recognizes Ronnie from Donna's group and tells the room keeper that he would like a room on the third floor.
After Ronnie gives them the keys the girls want to go up to their room to freshen up. Mr."Ramsly" (A.K.A the killer) see's Donna and her friends go into their room, and when he is at the door of the room he was assigned he takes out his card key and his pocket knife and cuts the magnetic strip of the card. He calls the housekeeper in the hallways and tells her his room key is broken. And she tells him that the card was cut. So she uses her master key to open the door and then he tells her that he would like more bath towels.
As the house keeper is in the bathroom putting in towels it is dead silent and she turns around and the killer takes out his pocket knife and stabs her in the stomach and covers her mouth so she cannot be heard.
He stashes her body some where and waits for Donna and her friends to come of out of their room. He watches them leave the room.
A few minutes later in the ballroom Clair and her date Michael are arguing about leaving for college and then Clair tell's Donna about their situation and Claire goes up to the room to freshen up.
While Claire is in the bathroom she hears the sound of the door opening and she calls to see if it is Donna. When she gets no answer she walks out to see if anyone else is in the room and then she turns around and the killer is behind her and stabs her in her stomach 3 times.
When Claire doesn't come back downstairs, Michael goes upstairs to see Claire. He thinks he hears her in the bathroom and tells her to come out and when she doesn't he sits down on the couch and waits for her, when he hears the door creak he thinks she is coming out, but the killer was in the bathroom. So Michael is looking around the room for Claire, and then when Michael turns around the killer pops out and stabs Michael and kills him.
Then in the hotel lobby the person at the front desk tells one of the other house keepers that he can't get a response from Gloria, which is the house keeper that got killed. The other house keeper tells the man at the front desk he will check for her when he is up at the floor she was last seen on. When he arrives up there he see's the killer coming out of Donna's room and he walks to his room. As the killer is about to go into his own room the male house keeper asks if he has seen the female house keeper, the killer replies "she is in my room turning down the bed" and when the male house keeper walks in the killer closes the door and kills the male house keeper
Later on they are discussing about how it is taking Micheal and Clair so long to come downstairs. Then the P.E. teacher announces that they are about to announce king and queen, when Ronnie decides to go upstairs with Lisa so they can have some alone time.
On their way up there Lisa bumps into the killer, he ducks his head quickly and Lisa stares at him for a few minutes trying to remember where she has seen him before. Once they are in their room they lay on the bed and start making out and and then Lisa opens her eye's and says something signifying that she is surprised and scared then she tells Ronnie that she has to go tell Donna something. Ronnie says "of all times" and pulls out an engagement ring.
When Lisa runs out of the room she slams the elevator button waiting for the elevator to open then she see's the door open that leads to the stairs and the killer comes out and she runs to the other stairs. While she is running she trips down the stairs and gets back up. She runs to the base or contruction level hiding from him. Ronnie starts to look for Lisa; and the elevator he takes ends up leading him to the contruction level. He calls out for Lisa but doesn't leave the elevator he is in, then the elevator closes. When Lisa thinks the coast is clear she gets up and runs only to be startled by a bunch of pigeons. Then she starts running again and bumps into paint buckets and makes a whole bunch of noise. Thinking that the killer is behind her she starts running and is looking behind her not looking forward she bumps right into the killer and he slits her throat.
A few minutes later, Detective Nash gets Detective Winn to follow him and a police officer to the parking lot. The police officer takes them to a car and he opens the trunk; there is a dead body in the trunk. The officer tells the story of a person that ended up missing the day the killer escaped from jail and how the dead body is mssing their clothes and their wallet, then the officer tells the detectives that the dead body is James Ramsly, the name of the person the killer checked into the hotel as.
Back at the dance they are about to announce kind and queen when Detective Winn sounds off the evacuation alarm right before they announce them. As everyone is leaving Donna tells Rick, Crissy's date(Lutz) that if Bobby is looking for her, she went up to her room to get her mothers shawl that her aunt gave her.
While she is up in her room she goes to her closet to get her purse and drops something, when she bends over the killer is right behind her. Then she turns around and there is nothing behind her, then she closes the closet door and see's his reflection in the mirror, and he says "Donna, I've missed you" and she screams and runs around the room into another part of the room and looks the doors.
The killer grabs the fire extinguisher in the halls and breaks down the door, then Donna runs under the bed to hide again. Once the killer is in the room he is looking for Donna and and while Donna is under the bed she scoots further away from the edge and bumps into something and when she turns her head that something is Claire's dead body. As Donna tries to hold in her scream she lets out a small whimper and the killer turns around and looks at the beds and goes to the opposite one Donna is under.
When he looks under Donna runs from under the bed and escapes out of the room bumping into the Detectives. In a frantic tone she tells them that the killer is in there. They escort her downstairs but don't see the killer in the room. Once Donna is outside, Bobby see's her and hugs her and they get into a police car and before they leave Donna tell's Ronnie that Claire is dead.
They bring a S.W.A.T team in the hotel and look every where for the killer and the once they receive word that the killer hasn't been found blood starts to drip from the air conditioning vent in Donna's room where the Detectives are and when they open it the body of the male house keeper falls out, but he doesn't have his uniform on. And then Detective Winn starts thinking and comes to realize that the killer walked right past him when the employees were exiting the building during the S.W.A.T search and the killer was wearing the house keepers uniform.
Detective Winn calls Nash and tells him that the killer escaped from the hotel and is on his way to Donna's house, so they have the house completely gaurded. About 20 minutes later the phone line's to the house got cut unexpectadly but no one knows when it happens, and Donna and her boyfriend are sleep in Donna's room and Donna wakes up and looks at the television and then looks out her window where she see's Nash wiping his eyes and then she goes into her bathroom to take her anxiety pills and when she closes the medicine cabinet the killer is behind her and she slams her head into the mirror. Then she wakes up, it was only a dream. When she wakes up and looks at the television the same show that was on in her dream is on, when she looks out her window Nash is wiping his eye and then when she goes in her bathroom and takes her pills she hesitates to close the cabinet but there is nothing behind her, but her window is open in her bathroom, she closes it and gets back in her bed.
When she tries to hug Bobby he doesnt move, so she pushes him a little revealing the slit on his throat. Donna covers her mouth and lets out a small shriek. Before she see's the dead boyfriend Winn pulls up to Nashes car and see's that Nash has also been killed. Then Winn goes inside; Donna see's a shadow and starts to walk in her closet and closes the door. When she see's that it is Winn's shadow she starts to step out when the killer grabs her and covers her mouth. Winn calls for Donna but she can't say anything, then the killer asks if she is ready to come with him and she says yes. Then Donna's aunt and uncle scream and Winn runs to them and they see that one of the security gaurds was killed. As Donna and the killer open the closet door and are about to leave Donna bites his hand and starts to run but she trips and he slips to pick her up and then she kicks him in the face and Winn hears Donna scream and he runs to the room where the killer is on top of Donna about to stab her then the killer gets shot once in the chest, but he is still alive so he get shot six other times by Detective Winn. And Winn tells Donna that it's over. And the movie ends.