Government officials discover a horrible plot: the Chinese are tunneling their way to the United States.
Cmdr. Jonathan Shaw
Tila Yung
Adm. Felix Hillebrand
Arnold Kramer
Sgt. Marvin Mulberry
Gen. Chan Lu
Dr. Kengh Lee
Sgt. Seth Hawkins
Maj. Frank Cannon
Lt. Cmdr. Vance Cassidy (as Edward Bishop)
Col. Talbot Wilson
Meg Webson
Dr. Arnn
Maj. Chai
Bomb Train Commander
Dr. Galissi
Susan Kramer
Broadcaster
Matron
Matron's Friend
Lanchek
Mine Foreman
Police
Police
Nurse
