Charley Brewster, is a normal, average teenager living with his divorced mother in a unnamed suburban township. One evening, Charley looks out his window and sees his new neighbors moving in the next door and appear to be carrying what looks like a coffin. Intreged with his new neighbors, Charley begins to spy on them.
One day, a young woman (obivously a call girl) shows up at Charley's house by accident looking for another address and Charley directs her to the house next door. The next morning at school, Charley sees a news broadcast about the police finding "another murder victim" from an unknown serial killer who decapitates female victims and drains the bodies of blood.
Another evening later, Charley, suspecting something sinister about his new neighbors, spies on the house next door and sees Jerry Dandridge bitting the neck of a young teenage girl. He tells his mother what he saw, but she passes it off as Charley's imagination. Charley tries to tell his friend "Evil Ed", and girlfriend Amy Peterson, but neither of them believe him, and begin to worry about Charley's mental well being.
Another day later, Charley calls the police with information about one of the murder victims and a detective accompanies him to the house where they meet Billy Cole, Jerry Dandridge's "roommate" who lets them in and shows them around the house. Finding nothing, the detective decides to leave, but Charley tells him to check the basement, which Billy seem adament about letting them go down there. The detective forces Charley to leave with him and tells him not to ever call on him again, thinking that Charley has an overactive imagination.
Suspecting that Jerry Dandridge is a vampire, he seeks advice from Evil Ed about how to fight vampires. Evil Ed tells him, from watching movies and documentaries about suspected vampires, that vampires are super strong, have no heartbeat or pulse, have vulnerabilites to holy water and crosses. They also cast no reflection in a mirror and they and can only be killed by fire, decapitation, sunlight, or a wooden stake through the heart. Ed also tells Charley that a vampire cannot enter a person's home without an invitation.
Charley goes home, but finds Jerry Dandridge in his living room waiting for him... having been invited in by Charley's mother. Dandridge is seemingly friendly and tells Mrs. Brewster about Charley showing up at his house today, and she reprimands Charley not to do it again.
That evening, Charley begins to fortify the house, knowing that Dandridge can enter whenever he feels like it. However, Dandridge enters the house from a second floor window and hides in a closet in Charley's bedroom. When Charley gets ready for bed, Dandridge suprises him and threatens to kill him for snooping around and nearly revealing his secret that he indeed is a vampire. When Dandridge tries to choke Charley to death, he stabs the vampire in his right hand with a pensil. Wounded and angry, Jerry Dandridge terrorizes Charley by revealing his true vampire demonic image, complete with red eyes, fangs, claws, and a roaring with a wolf-like rage, but waking up Charley's mother. Dandridge flees and threatens to kill Charley tomorrow night.
The next morning, Charley then seeks out help of favorite vampire killer, Peter Vincent, a former actor who hosts TV segments of horror movies that Charley watches and who claims to be a real vampire hunter. Charley confronts Vincent at the studio where he works and tells him that his neighbor is a vampire and is going to kill him. Vincent, like everyone else, brushes off Charley's claims as an overeager teen with an overactive imagination.
Charley does not go to school that day (because he finds his car totaled after Dandridge apparently trashed it the other night after their confrontation). Evil Ed and Amy visit Charley at his house and finds him secluded in his bedroom with crosses hanging everywhere. Hearing him talk about Peter Vincent, Evil Ed and Amy visit him at his apartment where they tell him about their friend and persuade him to prove to him that vampires don't exist. Vincent calls Dandridge at his house and offers to come over the next night with Charley to debunk Charley's theory that he is a vampire.
The following evening, Vincent, Charley, Ed, and Amy pay a visit to Dandridge's house where Billy lets them in and introduces them to Jerry Dandridge. Vincent tries to show Charley that Danridge is not vampire by having him drink a vital of holy water, as well as him holding a cross. Charley is still not convinced and says that crosses only work on vampires if a person has faith to use it, and the holy water that Dandridge just drank isn't real holy water. However, after Vincent sees Jerry casts no reflection in his small compact mirror he gets scared, and gathers up Amy, Charley, and Ed, and they all leave. Mr. Vincent hurries to his car, and then he drives away fast. Dandridge finds the mirror dropped by Vincent on his way out and leaves as well.
As Charley, Amy and Ed walk away, Evil Ed decides to leave Charley and Amy by walking in a dark alley. He runs down an alley, and it gets darker. All the sudden Jerry Dandridge appears, who wants Ed to become a vampire.
At Peter Vincent's apartment, he huddles scared and tries to shake it off, from feeling scared. Just then Evil Ed knocks on Peter Vincent's door. Vincent opens it, and begins conversing to Evil Ed casually, as he knows nothing of the hideous, undead Evil Ed is now. Suddenly Evil Ed attacks Mr. Vincent, who places a cross upon Evil Ed's forehead, which burns. A scalded Evil Ed slinks away, threatening Mr. Vincent by telling his "Master".
Charley and Amy find Dandridge following them and he chases them to a local nightclub where Dandridge sees that Amy resembles his lost love. He uses his vampire charm to hypnotize her and dance with him. When Charley intervenes, Dandridge restrains him and two bouncers appear, in which Danridge morphs into his fanged, red-eyed vampire self and kills both bounders with his superhuman strenght. Dandridge escapes from the nightclub in the confusion and chaos with Amy, and he and tells Charley to meet him later at his house or he will kill her.
Charley runs back to Mr. Vincent, who makes him grab a cross before he enters his apartment. Charley persuades Peter Vincent that they must confront Dandridge and kill him before the night is over. The duo get ready, and go to Jerry's house. By then, he has already turned Amy into a half-vampire. As Charley and Vincent enter the house, Dandridge appears on the top of the stairs and says: "welcome to"Fright Night"... for real. Vincent hesitates for a moment, and his faith Is too weak to keep Dandridge at bay with his cross. However Charley has faith and the vampire covers in fear from his crucifix. But Billy Cole comes to his master's aid and knocks Charley off the staircase, rendering him unconscious.
Vincent panics and runs to Charley's house. Charley wakes up to find himself locked in a room with Amy (who is now a half-vampire). Dandridge leaves a stake for Charley, giving him a choice:to kill Amy or not and risk getting killed by her when she fully turns in the morning.
Vincent flees to Charley's house to hide out, only to be confronted by Evil Ed, who transforms himself into a wolf and attacks Vincent again. Vincent defends himself by breaking a wooden table leg and kills Evil Ed by stabbing him through the heart, who then morphs back into his human form as he dies.
Vincent then returns to the Dandridge house where he frees Charley and they confront Billy again. Vincent shoots him several times with a gun, but Billy (a sort of zombie-like slave/familiar) keeps advancing towards them, and Charley finally kills him with Vincent's wooden stake by stabbing him through the heart in which Billy melts into a gooey mess of blood and green slime.
Charley and Vincent have another confrontation with Dandridge, who is kept at bay with their crucifix's, and they see that dawn is approaching. Dandridge transforms himself into a bat and flies away. Charley and Vincent venture down to the basement to find Dandridge's coffin to kill him while he sleeps. Just when they find the coffin, Amy, now a fully turned vampire, enters and attacks them. While Charley tries to keep her away, Vincent manages to open Jerry Dandridge's coffin and tries to drive his wooden stake through his heart, but Dandridge wakes up and Vincent stabs him, but misses his heard. The vampire rises from his coffin, pulls out the wooden stake and breaks in two. But when he attacks Vincent, Charley begins smashing in all the basement windows, allowing the sunlight to hit Dandridge. Using a mirror, they reflect the sunlight and finally manage to kill Dandridge by blasting him with the rays and he bursts into flames and within seconds his body is redused to dust and bones. With Jerry Dandridge's death, the still-alive Amy is apparently released from his curse and becomes human once again.
In the final scene, the movie ends just where it began with Charley and Amy back in his room watching a horror movie hosted by Peter Vincent on the TV, who announces his dedicating the movie to his friend Charley for making him belive that vampires are real. The movie is left open ended, when Charley looks out at the Dandridge house next door, now dark and vacant, he briefly sees a pair of red eyes staring at him from the darkness. But instead of telling Amy, he decides to let it go and goes back to her for another make-out session on his bed. The voice of Evil Ed is heard saying "oh you're so cool Brewster!"