On Halloween, 31 Oct 1978, in Haddonfield, IL, babysitter Laurie Strode has stabbed the Boogeyman, aka Michael Myers. A wounded Laurie sends her frightened charges, Tommy Doyle and Lindsey Wallace, to get help. Dr. Sam Loomis, Michael’s long-time psychiatrist, searches for Michael and sees the kids run outside. Inside, Michael, wearing a Halloween mask, silently gets up and attacks Laurie. The two struggle before Loomis rushes up the stairs and shoots Michael. The bullets send Michael crashing through a window. He falls to the lawn below where he lays lifeless. A tearful Laurie declares he was the Boogeyman and Loomis agrees. Loomis surveys the lawn for Michael’s body but it is gone. Michael walks through nearby neighborhoods and kills a teenage girl as Loomis and Sheriff Leigh Brackett frantically search for him. Paramedics Jimmy and Budd take Laurie to Haddonfield Memorial Hospital where Dr. Mixter, who is probably drunk, examines her. Laurie begs Dr. Mixter not to put her to sleep but he gives her the shot anyway. Loomis and Sheriff Brackett spot a man wearing Halloween mask exactly like Michael’s. Loomis pulls his gun but the Sheriff stops him. A cop car suddenly smashes into the man and they crash into a van. Loomis and the Sheriff examine the burning corpse but cannot tell if it is Michael. Another cop arrives to tell the Sheriff that bodies of three teens have been found and one is the Sheriff’s daughter, Annie. At the hospital, Budd, a nurse, Jill, and the night guard, Mr. Garrett, watch news coverage at the nurses’ station. Jimmy slips into Laurie’s room but the head nurse, Mrs. Alves, tells him to leave. She also tells Laurie that her leg is not broken, it is just a cracked bone. Jimmy leaves for another call with Budd, and they are wheeling out Annie’s body as Sheriff Brackett, Loomis and the cop arrive. The grief-stricken Sheriff leaves, blaming Loomis for letting Michael out. Loomis is not sure Michael died in the car crash and tells the cop to find a dentist to meet them at the Coroner’s office. Across town, a nurse, Karen, leaves a Halloween party and is late for her shift. She arrives at the hospital, grabs her uniform and rushes inside as Michael arrives behind her. In the break room, Budd smokes a joint as he, Jimmy and a student nurse, Janet, watch TV coverage. In the security office, Mr. Garrett reads a magazine and does not see Michael on the monitors. Michael watches, unseen, as Karen is scolded by Mrs. Alves for being late. Jimmy sneaks back into Laurie’s room. He tells her about Michael’s escape from the mental hospital, and Laurie wonders why Michael is after her. They are interrupted by Mrs. Alves who has not been able to reach Laurie’s parents. Michael wanders the hospital’s halls as Mrs. Alves sends Janet to tell Mr. Garrett about the phone trouble. Mr. Garrett hands Janet a walkie-talkie to use while he checks the phones. Janet does not know how to use it but reluctantly waits. When Mr. Garrett discovers a storeroom with a broken padlock, he calls Janet on the walkie-talkie and tells her to drive to the Sheriff’s station. Janet, however, only gets static. Mr. Garrett continues to investigate until Michael suddenly appears with a hammer and slams it into Mr. Garrett’s head. At the morgue, Loomis, the cop and a dentist check the teeth of the burned body. The dentist says the victim is 17-18 years old. Michael is twenty-one, so they must assume Michael is still alive. Loomis and the cop decide to check out the Myers house where Loomis recounts Michael’s back-story of murdering his sister with a butcher knife. Loomis is interrupted by two teens worried about their missing friend, Bennett Tramer, who left a party drunk and wearing a Halloween mask. Loomis and the cop realize Tramer might be the burned corpse. News arrives about a break-in at the elementary school and they leave to investigate. At the hospital, a buzzing light startles Karen. She checks on the “patient” and is grabbed by Budd who wants to meet her in the physical therapy room. Karen is initially hesitant but agrees. Laurie has dreams of blood interspersed with her younger self hanging laundry with her mother who says, “I am not your mother.” Then young Laurie approaches young Michael who sits and stares out the window. He turns to look at her and more images of blood awaken Laurie. She is groggy, however, and quickly drops back to sleep. Budd soaks in the Jacuzzi as Karen undresses, turns off the light and joins him. In the dressing area, Michael turns up the heat. Budd and Karen start to make out but the water is too hot so Budd checks on the heat while Karen towels off. Michael strangles Budd, then comes up behind Karen and pushes her head into the Jacuzzi where she is boiled and drowned. At the school, “SAMHAIN” is written in blood on the blackboard and Loomis explains it is Celtic for “Lord of the Dead.” Marion Chambers from Smith’s Grove sanitarium arrives with a Marshal to take Loomis back to the sanitarium. At the hospital, Jimmy discovers Laurie is catatonic, perhaps from a reaction to medication. Janet finds Dr. Mixter who was killed with a syringe in the eye, and Michael kills Janet with a syringe of air to her temple. As Jimmy searches for Mrs. Alves, Jill leaves Laurie to check on a buzzing light. Michael enters Laurie’s room and stabs the bed repeatedly with a scalpel but discovers he has stabbed pillows. Laurie limps down a hallway and hides in an empty room, huddled against the wall. Michael moves at a deliberate pace through the hallways. Jill discovers Laurie is missing and is startled by Jimmy who says he cannot find anyone. Michael watches, unseen, as Jimmy sends Jill to the Sheriff’s. Jimmy finds Mrs. Alves’ body strapped to a gurney, her blood drained by a tube in her arm. Jimmy slips on all the blood, lands hard and is knocked out. Jill’s car will not start and every tire in the parking lot is flat. She runs back inside and sees Laurie limping down the hallway. Laurie turns to see Michael step behind Jill and stab her. Laurie races to the basement. She hides in a utility room but backs into Mr. Garrett’s body and screams. Michael comes into the room so Laurie climbs to a small upper window and pulls herself through while Michael tries to hack her feet with a knife. Laurie runs for the elevator, frantically waits for it and barely gets away. She runs outside and hides on the passenger floor of a car. In the Marshal’s car, Marion tells Loomis of a secret file, just unsealed. Michael Myers is Laurie Strodes’ brother. Laurie was two when Michael was committed. Her parents died two years later and the Strodes adopted Laurie. The file was sealed for their protection. Loomis realizes Michael is back to kill his sister and forces the Marshal to drive to the hospital. Jimmy, still dazed, gets into the car in which Laurie is hiding, but he cannot start the car and passes out. Laurie crawls out as Loomis, Marion and the Marshal arrive. They do not hear her and rush inside. Laurie limps across the parking lot with Michael in pursuit. Loomis lets her inside and quickly locks the glass door behind them. But Michael crashes through the glass and Loomis shoots him five times. Michael drops to the ground, apparently dead. Marion runs to call the cops on the Marshal’s radio. Michael suddenly sits up and slits the Marshal’s throat, then pursues Loomis and Laurie through the hospital. They hide in a Minor Surgery room and Loomis gives Laurie a gun. Michael breaks in and Loomis shoots, but the gun is empty. Michael stabs Loomis so Laurie shoots Michael twice in the face. As Michael clutches his bleeding eyes and swings his knife blindly, Loomis turns the valve on a nearby ether tank and Laurie does the same. Loomis pulls the oxygen and ether lines from the walls, orders Laurie to run, then raises his lighter. The room explodes. Laurie is sent flying down the hallway. She looks back as Michael, fully engulfed, walks from the flames before dropping, dead. Flames burn his Halloween mask. In the aftermath, Laurie is wheeled to another ambulance as the cops estimate ten are dead, so far.