A visiting son tries to warn his father and stepmother that they are being menaced by a living and intelligent pulse of electricity that moves from house to house and terrorizes the residents therein.
In a suburb in Los Angeles, California, the divorced Bill welcomes his beloved son David with his new wife Ellen to spend a few days with him.
David lives with his mother in Colorado, and befriends his neighbor Stevie. When Bill and Ellen have to go to a party, David prefers to stay home alone watching a baseball game on TV. Out of the blue, weird things happen at home with the TV and other electric appliances.
Then Stevie tells him that their neighbor went crazy and destroyed his house. David snoops around in the house and meets an old man, who tells him that there is a deadly and intelligent pulse of electricity running through the electrical grid. David is afraid and discloses the information to Bill and Ellen, but they do not believe in him.