Michael Myers (DAEG FAERCH) is a troubled, 10-year-old kid. Growing up in a white trash family in Haddonfield, Illinois, he must put up with put-downs by his older sister, Judith (HANNA HALL), and verbal abuse by their stepfather, Ronnie (WILLIAM FORSYTHE), who isn't above cussing out their mother, Deborah (SHERI MOON), a stripper at a local club.
When it appears the boy has been taking out his frustrations by killing animals, child psychologist Dr. Samuel Loomis (MALCOLM McDOWELL) is called in, but it's too late. Upset that he isn't taken out trick or treating, he kills Ronnie, Judith and her boyfriend, and then calmly waits for the police to arrive while holding his unharmed infant sister in his lap. Convicted and then committed for his crimes, Michael seems blasé about his murderous acts, a point that greatly disturbs Loomis.
The years pass, however, and with no progress delving into Michael's psyche, Loomis gives up on Michael (TYLER MANE) who's now grown into a hulking but mute man who spends his time fashioning various masks, a need stemming from his childhood to cover up his previously self-proclaimed ugliness. After killing much of the security detail at the sanatorium, Michael escapes and returns to his hometown where he hopes to find his baby sister.
She's now grown up into high school senior Laurie Strode (SCOUT TAYLOR-COMPTON) who isn't dating anyone, but lives variously through her best friends, Annie (DANIELLE HARRIS) and Lynda (KRISTINA KLEBE) who mock Michael when they see him hanging out in the neighborhood, not realizing who he is or what he's capable of doing.
As Loomis follows Michael's trail and tries to warn Annie's dad, Sheriff Lee Brackett (BRAD DOURIF), about the pending danger, Laurie and her friends go about their usual activities, unaware of what's about to unfold on their sleepy suburban street on Halloween night.