Two decades after surviving a massacre on October 31, 1978, former babysitter Laurie Strode, now the dean of a Northern California private school with an assumed name, must battle the Shape one last time, as the life of her own son hangs in the balance.
After failing to kill stubborn survivor Laurie and taking a bullet or six from former psychiatrist Dr. Sam Loomis, Michael Myers has followed Laurie to the Haddonfield Memorial Hospital, where she's been admitted for Myers' attempt on her life. The institution proves to be particularly suited to serial killers, however, as Myers cuts, stabs and slashes his way through hospital staff to reach his favorite victim.
Michael manages to free himself from Laurie Strode's trap to resume his ritual bloodbath. As she fights for her life from injuries from their last encounter, she inspires her daughter Karen, her granddaughter Allyson, and all of Haddonfield to rise up against the unstoppable monster.
Fifteen years after murdering his sister on Halloween Night 1963, Michael Myers escapes from a mental hospital and returns to the small town of Haddonfield, Illinois to kill again.