It's like a smart pulse of electricity is moving from house to house. It makes people afraid by taking over the appliances and killing them or making them wreck the house in an effort to destroy it. Then, it moves along the power lines to the next house, and the terror starts again, over and over. The pulse is now in the home of a boy's divorced father, whom he is visiting. It has already wrecked a house in a quiet neighborhood. It slowly takes over everything, hurts the stepmother, and traps father and son, who have to fight their way out.