"Government officials discover a horrible plot: the Chinese are tunneling their way to the United States."
Kerwin Mathews
as Cmdr. Jonathan Shaw
Viviane Ventura
as Tila Yung
Robert Ayres
as Adm. Felix Hillebrand
Peter Arne
as Arnold Kramer
Al Mulock
as Sgt. Marvin Mulberry
Martin Benson
as Gen. Chan Lu
Peter Elliott
as Dr. Kengh Lee
Earl Cameron
as Sgt. Seth Hawkins
John Brandon
as Maj. Frank Cannon
Ed Bishop
as Lt. Cmdr. Vance Cassidy (as Edward Bishop)
Bill Nagy
as Col. Talbot Wilson
Sarah Brackett
as Meg Webson
Paula Li Shiu
as Dr. Arnn
David Spenser
as Maj. Chai
Michael McStay
as Bomb Train Commander
Carl Jaffe
as Dr. Galissi
Norma West
as Susan Kramer
Larry Cross
as Broadcaster
Bessie Love
as Matron
Bee Duffell
as Matron's Friend
Bill Hutchinson
as Lanchek
Martin Terry
as Mine Foreman
Frank Lieberman
as Police
Roy Pattison
Chela Matthison
as Nurse
Charles F. Vetter
Screenplay
Story
Montgomery Tully
Director
Tom Howard
Special Effects
Kenneth Talbot
Director of Photography
Pat Kelly
Assistant Director
J.B. Smith
Sound Recordist
Ken Jones
Music
Gerry Turner
Jim Morahan
Art Direction
A.W. Watkins
Recording Supervision
Charles Reynolds
Producer
Executive Producer
Alan McCabe
Camera Operator
Ronnie Bear
Production Manager
Sidney Stone
Supervising Editor
