During the Vietnam War U.S. decoder Kate Meredith is plagued with guilt when her husband coerces her to pass information to him and the Viet Cong.
A former World War II pilot, now the owner of a travel agency in Hong Kong, gets involved in espionage trying to help a Chinese woman locate her son.
Government officials discover a horrible plot: the Chinese are tunneling their way to the United States.
A secret, high-technology international agency called SHADO defends Earth from alien invaders.
