How tenuous is man's hold on civilization when survival becomes an issue? When the lights go out and stay out for several days, suburbanites Matthew and Annie learn the hard way that man is "by nature" a predatory creature. Matthew's long-time friend, Joe, happens by on the second day and a rivalry between the two friends simmers as Annie cares for her sick baby. When rumors of looting spread through the neighborhood, the two men buy a shotgun for protection but Annie throws it in the pool. Later, that same night, Joe hears a prowler downstairs and awakens Matthew. They chase the stranger from the house and out into the street where a neighbor shoots him to death. No longer safe in their own home, they decide to drive to Annie's parents some 500 miles away. Before they reach their destination, more trouble comes their way when they stop to siphon gas from an abandoned car and discover the driver in the back seat... Is this what is meant by "man's inhumanity to man?"