On October 31, 1978, Deputy Frank Hawkins accidentally shoots his partner dead while trying to save him from Michael Myers. He also prevents Dr. Samuel Loomis from executing Michael. Forty years later, on October 31, 2018, after being stabbed and left to die by Dr. Ranbir Sartain, Hawkins is found by Cameron Elam, who calls an ambulance. Hawkins regrets not allowing Michael's execution and vows to kill him.
Meanwhile, Tommy Doyle celebrates the 40th anniversary of Michael's imprisonment along with fellow survivors Marion Chambers, Lindsey Wallace, and Cameron's father, Lonnie Elam, having each survived an encounter with Michael in 1978. Firefighters responding to Laurie Strode's burning house inadvertently release Michael, who slaughters them with their own equipment. Laurie, her daughter Karen, and her granddaughter Allyson are taken to Haddonfield Memorial Hospital, where Laurie undergoes emergency surgery, as Michael murders Laurie's neighbors before making his way back to Haddonfield.
Tommy, Marion, Lindsey, and Lonnie learn of Michael's killing spree through a wireless emergency alert. Bar patron Vanessa supposedly encounters Michael in her car, but the driver crashes and escapes unnoticed. Tommy forms a mob of vengeful Haddonfield residents to hunt down and kill Michael. Karen is informed that Michael is still alive and withholds that information from Laurie to allow her to recover. Allyson reconciles with Cameron, her ex-boyfriend, and she joins Tommy's mob to avenge her own father's death. Laurie and Hawkins both awaken in the same room and reminisce about their former relationship.
While warning the Haddonfield community to stay inside their houses, Marion, Vanessa, and her husband Marcus are killed by Michael. Lindsey escapes and is found alive by Tommy, Lonnie, Allyson, and Cameron. The group map out Michael's path and his victims' location and deduce that he is heading towards his childhood home. Tommy takes Lindsey to the hospital and reunites with former Haddonfield sheriff Leigh Brackett, whose daughter Annie was killed in 1978, and informs Laurie about Michael's survival. Across town, Michael murders the current owners of his home as Laurie prepares to leave the hospital.
Lance Tovoli, a fugitive convict from Smith's Grove Psychiatric Hospital and Vanessa's car driver, who escaped alongside Michael when their bus crashed, arrives and is mistaken for Michael. Tommy's mob pursue him through the hospital before Karen realizes that he is not Michael. Despite her attempts to calm the mob and help Lance, he jumps out a window to his death. Laurie urges Karen to work with Tommy and Brackett to hunt Michael down. Elsewhere, Lonnie heads in alone to Michael's home and is killed. Allyson and Cameron rush inside and find his corpse before being attacked by Michael, who murders Cameron.
As Michael prepares to kill Allyson, Karen stabs him in the back with a pitchfork, steals his mask, and taunts him to follow her. She leads Michael into Tommy's mob, who swarm, attack, and seemingly kill him. When the mob disperses, Michael recovers and massacres the entire mob, including Tommy and Brackett. Back at Michael's home, Karen goes upstairs to investigate while Allyson receives medical attention. Michael appears and stabs Karen to death in Judith Myers's old bedroom as Laurie stares out of her hospital room.
Directors David Gordon Green
Starring Jamie Lee Curtis, Judy Greer, Andi Matichak
Genres Horror, Suspense