Father Stanley Unwin is invited to try and prevent a possible sabotage at a demonstration of the Army's latest and most advanced tank and he goes disguised as an Army padre. As the exercise progresses, it becomes clear to Father Unwin that someone has programmed the tank to attack the blockhouse where top NATO officials are watching. He goes to the control room where he finds that a senior officer has destroyed the computer and the tank can no longer be remote controlled nor stopped from its destructive mission.