On Halloween night 1963, in Haddonfield, Illinois, 6-year-old Michael Myers (Will Sandin), dressed in a clown costume and mask, murders his older sister Judith (Sandy Johnson) by stabbing her with a kitchen knife in their home. Fifteen years later, on October 30, 1978, 21-year-old Michael (Nick Castle) escapes from Warren County Smith's Grove Sanitarium, stealing a car that was to take him to court.
The following day, Halloween, Michael, wearing a mechanic's uniform and a white mask, stalks high school student Laurie Strode (Jamie Lee Curtis - Prom Night ) after she and Tommy Doyle (Brian Andrews) drop off a key at his former house so her father can sell it. Throughout the day, Laurie notices Michael following her, but her friends Annie Brackett (Nancy Kyes) and Lynda Van der Klok (P.J. Soles) dismiss her concerns. Michael's psychiatrist, Dr. Sam Loomis (Donald Pleasence - The House of Usher ), arrives in Haddonfield to look for him. After finding that Judith Myers' headstone is missing, Loomis meets with Annie's father, Sheriff Leigh Brackett (Charles Cyphers). The two go to Michael's house, where Loomis warns the sheriff about the danger Michael poses. Sheriff Brackett patrols the streets, while Loomis waits and watches the house.
Later that night, Laurie goes over to babysit Tommy Doyle while Annie babysits Lindsey Wallace (Kyle Richards - Eaten Alive ) just across the street, unaware that Michael is watching them. When Annie's boyfriend Paul calls her to come and pick him up, she takes Lindsey over to the Doyle house to spend the night with Laurie and Tommy. Annie is just about to leave in her car when Michael, who hid in the back seat, strangles her before slashing her throat, killing her.
Soon after, Lynda and her boyfriend Bob Simms (John M. Graham) arrive at the Wallace house. After having sex, Bob goes downstairs to get a beer for Lynda, but Michael stabs him with a knife, pinning him to the wall and killing him. Michael then poses as Bob in a ghost costume and confronts Lynda, who teases him, to no effect. Annoyed, Lynda calls Laurie; just as Laurie picks up, Michael strangles Lynda to death with the telephone cord. Meanwhile, Loomis discovers the car Michael stole and begins combing the streets.
After putting Tommy and Lindsey to bed, a suspicious Laurie goes over to the Wallace house where she finds the bodies of her friends in an upstairs bedroom, as well as Judith Myer's headstone. As a horrified Laurie cowers in the hallway, Michael suddenly appears and attacks her, slashing her arm and causing her to fall down a flight of stairs. Barely escaping, Laurie races back to the Doyle house. Michael gets in through an open window and attacks her again, but Laurie manages to fend him off long enough for Tommy and Lindsey to escape. Loomis sees them fleeing the house, and goes to investigate, finding Michael and Laurie fighting upstairs. Loomis shoots Michael six times, knocking him off the balcony. A frightened Laurie asks, "Was it the boogeyman?" to which Loomis replies, "As a matter of fact, it was." However, when Loomis goes to check Michael's body, he finds it missing. Places where Michael had previously been are shown as his breathing is heard, indicating he could be anywhere.
Halloween is a 1978 American independent slasher film directed and scored by John Carpenter, co-written with producer Debra Hill, and starring Donald Pleasence and Jamie Lee Curtis in her film debut.