On Halloween night, 1963, in Haddonfield, Illinois, six year old Michael Myers perused the kitchen for a large butcher knife as his sister, Judith, was having carnal relations with her boyfriend upstairs. Waiting until Judith’s boyfriend has satisfied himself and then stolen off into the night, young Michael donned the clown mask of his Halloween costume, and then crept upstairs and walked into Judith’s bedroom to repeatedly stab his sister until she bled to death. Perhaps he’d been upset that she’d chosen sex over taking him trick-or-treating. Regardless, this act of savagery placed him on his chosen career path of psychotic serial killer. After killing Judith, he unapologetically waits on the front porch for his parents to arrive home from their relaxing evening out.

Fifteen years later, a fully grown Michael—who hasn’t uttered a word since his fratricide—escapes from the psychiatric ward he’s called home for the last decade and a half. He finds his way back to Haddonfield, killing a trucker for his blue coveralls and inexplicably stealing a Halloween mask from a costume shop while en route, and then proceeds to stalk high school student Laurie Strode, a shy and demure girl of seventeen. Laurie first notices Michael watching her outside of her classroom at school, and then later in the backyard of her house. Her friends think she’s being silly, and Michael seems to have an uncanny knack for disappearing like Batman whenever Laurie gives him a double take.

Meanwhile, the only person who seems to see the impending danger is Dr. Sam Loomis, Michael’s childhood psychiatrist and the only one who recognizes the significance that today is Halloween. He approaches Sheriff Leigh Bracket in order to conscript him into his cause. Sheriff Bracket is also the father of Laurie’s best friend, Annie. He reluctantly agrees to aid Loomis in his search for the wayward Michael.

That night Laurie and Annie are both babysitting two trick-or-treaters: Tommy Doyle and Lindsey Wallace. Annie leaves Lindsey in Laurie’s care while she goes to pick up her boyfriend, but she doesn’t make it very far. Michael cuts her throat before she can even start the car. Tommy, a strong believer in “The Boogeyman”, sees Michael carrying Annie’s body in the street, but his horror is dismissed by Laurie as being fantastic. Laurie, probably the only person in all of Haddonfield besides Loomis to have reason to believe Tommy, goes about her business as Michael, across the street at the Wallace house, impales her friend Bob with a kitchen knife and then chokes the life out of her other friend Lydia while dressed as a white sheet ghost.

Laurie is eventually overcome with a feeling of trepidation that causes her to cross the street and enter the Wallace house. There she finds the splayed out bodies of her three friends ornamented with the stolen headstone of Judith Myers. What ensues next is a bloody chase back across the street to the Doyle house, during which Laurie gets a few good stabs at Michael, but makes the repeated mistake of letting her guard down and turning her back to him once she’s under the impression that she’s killed him. She sends the children for help, ignoring Michael’s prone form on the floor, and then leans against a door jamb to catch her breath. A weaponless Michael rises and then proceeds to strangle Laurie with his bare hands until Dr. Loomis, who’s heard the screams of the children in the street and has entered the Doyle’s home, intervenes. After Laurie pulls Michael’s mask off (this is the only glimpse the audience will get of Michael’s face for the entirety of the series), Loomis unloads all six shots of his revolver on Michael, sending him off the balcony of the master bedroom where he lands on the front lawn. When Laurie asks her stranger-savior if that was the boogeyman, Loomis responds, “Yes, I do believe it was.” When Loomis moves to the balcony to view the body, he is surprised to find that Michael has disappeared.