A series of tornadoes in West Tennessee cripple the Helman-Klein Nuclear Power Plant by damaging a power transformer and a generator. This leaves the plant with very little power to operate. As an operator shuts down non-vital systems, which include the electric pumps, a second tornado hits the plant, damaging the diesel pumps. Meanwhile Campbell Maguire (Daniel Costello (actor)), the plant supervisor's young son, is caught in the twisters. His babysitter is killed and he runs away towards the plant on his bike.