HALLOWEEN

On October 29, 2018, infamous serial killer Michael Myers, who has been institutionalized at Smith's Grove Psychiatric Hospital for 40 years following his killing spree in Haddonfield, is being prepared for transfer to a different facility named Glass Hill. True crime podcasters Aaron Korey and Dana Haines visit the hospital, where Aaron displays Michael's mask to him, to no effect.

In Haddonfield, Laurie Strode still lives in fear of him, drinking heavily and rarely leaving her heavily fortified house. She has a strained relationship with her daughter Karen, whom the state took away from her when Karen was 12. Allyson, Laurie's granddaughter, tries to maintain a relationship with her grandmother. The night of October 30, as Michael is being transferred, the bus crashes and Michael escapes after murdering two people and stealing their truck.

On the morning of October 31, Michael sees Aaron and Dana visiting his sister Judith's grave. He kills them both, as well as a mechanic for his overalls, before recovering his mask from Aaron's car. Laurie learns of Michael's escape and attempts to warn Karen, but Karen dismisses her concerns, urging Laurie to move on.

That night, Allyson finds her boyfriend, Cameron, cheating on her at a party and leaves with his friend Oscar. Allyson's best friend Vicky and her boyfriend Dave are both killed by Michael. Deputy Frank Hawkins, who arrested Michael in 1978, and Laurie overhear the incident on radio and go over to the house. Laurie sees Michael for the first time in 40 years and shoots him before he flees. The police take Laurie, Karen, and her husband Ray to Laurie's home for protection.

Dr. Ranbir Sartain, Michael's psychiatrist and former student of Dr. Samuel Loomis, persuades Sheriff Barker to help in the hunt for Michael. Michael kills Oscar, but Hawkins and Sartain rescue Allyson. Deputy Hawkins incapacitates Michael and tries to kill him, but Dr. Sartain—who has become obsessed with Michael—attacks and leaves Hawkins for dead. It is revealed that he orchestrated Michael's escape to study him "in the wild". Dr. Sartain heads toward Laurie's home with an unconscious Michael and Allyson locked in the backseat together. Michael wakes up and kills Sartain while Allyson flees. Michael then kills the two police officers stationed outside Laurie's home and strangles Ray to death.

In Michael's showdown with Laurie, he stabs her and pushes her over a balcony. When he goes to check her body, he finds it missing, reminiscent of their first encounter decades earlier. Karen shoots him in the cheek before Laurie traps him inside the safe room with Karen and Allyson's help. The trio sets the house ablaze, and Laurie says goodbye to Michael before she faints. As her family takes her to the hospital, a final shot of the burning basement is shown, with Michael nowhere in sight. In a post-credits scene, Michael's breathing is heard, indicating that he has survived.

Laurie, Karen, and Allyson trap Michael Myers in the fortified basement of Laurie's home and set the house on fire, leaving him to perish as they escape.

The ending delivers a cathartic reversal of roles, with Laurie and her family using years of preparation to turn the hunter into the hunted. The fiery finale symbolizes both the literal and emotional purge of Michael's shadow from their lives, but the ambiguity of the final shots leaves the door ajar for evil to linger—true to the slasher tradition.