During a VIP visit to the headquarters of the Strategic Air Command (SAC), at Offutt Air Force Base in Omaha, Nebraska, the Air Force's Distant Early Warning Line indicates that an unidentified aircraft has intruded into American airspace. Shortly after, the "intruder" is identified as an off-course civilian airliner and the alert is cancelled, but a computer error causes one American bomber group to receive orders for an attack on Moscow. Attempts to rescind this order fail because a new Soviet countermeasure radio jamming American radio communications. With his orders apparently confirmed, Colonel Jack Grady, the US bomber group's commander, orders them to continue to their target.