After a big opening with Malcolm O'Keefe (Peter Jason) being straightjacketed in his own backyard, and hauled off to a mental institution, TRICK OR TREATS begins.
Linda (Jackelyn Giroux) arrives at her babysitting assignment with Malcolm's odd, practical joke-obsessed son, while his mum (Carrie Snodgress) and her new husband (David Carradine) attend an all-night Halloween party.
Simultaneously, Malcolm decides it would be a good night to break out of the draped-off, school cafeteria posing as a hospital, and seek his revenge. Obviously, this requires an ingenious disguise, stealth, and... well, maybe not. In no time, he's heading home, trying out every payphone along the way.
Meanwhile, Linda has her hands full with the most annoying boy ever born. She would be helped enormously by not falling for every prank the little monster pulls! Is Malcolm ever going to arrive? He sure takes his sweet time! He finally gets home, with 30 minutes of movie to spare! Let the -limited- mayhem unfold.
As murdering maniac / slasher films go, this one is a lengthy slog for very little payoff. Sure, Malcolm is crackers, and he kills a few people, but, he's more pitiful than terrifying. It's interesting that the first two thirds of the movie play out as more of a comedy, only to lower the boom during the finale...