S.H.A.D.O.: Bravery and guile, organisation and instant decision making are the qualities called upon by the hundreds of S.H.A.D.O. personnel, and only after valiant efforts in all these departments of human endeavor will the earth be once again safe from the alien threat. The alien crisis could develop at any time, and the technicians, scientists, controllers and operatives at S.H.A.D.O. HQ must remain on constant alert for the danger signs. The highly trained S.H.A.D.O. staff members control the destinies of countless men, women and children who might fall innocent prey to the greatest enemy the world has ever known. The valuable and complex machinery and equipment housed in the S.H.A.D.O. Control Centre is designed to save lives. And ironically, the very people it continues to protect can never be made aware of its function... for widespread knowledge of the S.H.A.D.O. operation and the Alien invasion could result in blind panic and total misunderstanding. Commander Ed Straker and his staff must wage a powerful and silent battle and their courage and devotion to duty must go unrewarded, for the S.H.A.D.O. password is 'secrecy'.