Dr. Daniel Challis (Tom Atkins) and Ellie Grimbridge (Stacey Nelkin) stumble onto a series of gruesome mu murders when her novelty salesman father, Conal Cochran (Dan O'Herlihy), is killed. Cochran is a demented toymaker who wants to return the holiday to its darker roots using his Silver Shamrock masks. His unspeakable scheme will unleash death and destruction across the country, unless Challis can stop him in time.
